ci: move GitHub Actions to their Node 24 majors

.github/dependabot.yml

@@ -0,0 +1,23 @@
+# Dependabot: keep the workflow pins on current majors, so hand-written
+# workflows cannot drift back onto end-of-life runtimes unnoticed.
+#
+# Two groups, the form QuantEcon/actions uses, so updates land as at most two
+# PRs a week: "github-actions" for minor/patch (low risk, merge together) and
+# "github-actions-major" for majors (read the release notes first).
+# `directory: /` covers .github/workflows/.
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 10
+    commit-message:
+      prefix: "⬆️"
+    groups:
+      github-actions:
+        patterns: ["*"]
+        update-types: [minor, patch]
+      github-actions-major:
+        patterns: ["*"]
+        update-types: [major]

.github/workflows/audit-dashboard.yml

@@ -38,7 +38,7 @@ jobs:
     outputs:
       warnings: ${{ steps.warnings.outputs.text }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           # Nothing under `lectures/` may be an LFS object (.gitattributes
           # scopes LFS to `sources/**`), and this job publishes `lectures/` to
@@ -49,7 +49,7 @@ jobs:
           # as pointer text everywhere else. It also keeps `sources/` — a 99 MiB
           # LFS object — off every run of this workflow.
           lfs: false
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       - run: pip install pyyaml
@@ -85,7 +85,7 @@ jobs:
           cp -r site/. _site/
           cp -r lectures _site/lectures
           cp audit.json _site/audit.json
-      - uses: actions/upload-pages-artifact@v3
+      - uses: actions/upload-pages-artifact@v5
         with:
           path: _site
 
@@ -100,11 +100,11 @@ jobs:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
     steps:
-      - uses: actions/configure-pages@v5
+      - uses: actions/configure-pages@v6
         with:
           enablement: true
       - id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v5
 
   # The strict build is this repo's drift alarm for 8 upstream lecture repos,
   # and the weekly schedule fires when nobody is watching. It worked exactly as

.github/workflows/consumed-file-check.yml

@@ -15,7 +15,7 @@ jobs:
   consumed-files:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           # `lfs: false` is the assertion, not a saving. A manifest records the
           # sha256 of the real bytes, so if a `lectures/` file is ever
@@ -34,7 +34,7 @@ jobs:
           # by mistake arrives as real bytes, hashes to something the README
           # does not record, and goes red.
           lfs: false
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       - run: pip install pyyaml

.github/workflows/refresh-snapshots.yml

@@ -58,10 +58,10 @@ jobs:
       all: ${{ steps.plan.outputs.all }}
       due: ${{ steps.plan.outputs.due }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           lfs: false
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       - run: pip install pyyaml
@@ -99,10 +99,10 @@ jobs:
     # A matrix cannot expose one output per leg, so a failing leg leaves its
     # failure.json + log as an artifact and the notify job reads those.
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           lfs: false
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       - run: pip install -r requirements.txt
@@ -130,7 +130,7 @@ jobs:
           exit "$code"
       - name: Keep the failure for the notifier
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: canary-failure-${{ matrix.snapshot.stem }}
           path: |
@@ -145,7 +145,7 @@ jobs:
     permissions:
       issues: write
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v8
         with:
           pattern: canary-failure-*
           path: failures
@@ -161,8 +161,13 @@ jobs:
           {
             echo "The weekly sources-alive canary failed. Nothing was written: every consumer keeps reading the last-good snapshot, so no lecture is affected — this is the alarm moving from the lecture repos' CI to here, doing its job."
             echo
-            for dir in failures/*/; do
-              [ -f "$dir/failure.json" ] || continue
+            # download-artifact v5+ unpacks a lone artifact straight into
+            # failures/ (one leg failed, the usual case) and several into
+            # failures/<name>/, so find each failure.json wherever it landed
+            # and read builder.log beside it. If nothing was uploaded (plan
+            # failed, or a leg failed before its builder ran) there is no
+            # failures/ and the loop finds nothing, as the old glob did.
+            while IFS= read -r dir; do
               dataset=$(jq -r .dataset "$dir/failure.json")
               builder=$(jq -r .builder "$dir/failure.json")
               kind=$(jq -r .kind "$dir/failure.json")
@@ -179,7 +184,7 @@ jobs:
               tail -n 15 "$dir/builder.log"
               echo '```'
               echo
-            done
+            done < <(find failures -type f -name failure.json -exec dirname {} \; 2>/dev/null | sort)
             echo "Run: $RUN_URL"
             echo
             echo "_Posted automatically. Later failures comment here rather than opening new issues, so close this once the canary is green._"
@@ -208,13 +213,13 @@ jobs:
         snapshot: ${{ fromJson(needs.plan.outputs.due) }}
     name: refresh (${{ matrix.snapshot.dataset }})
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           lfs: false
           # The PAT, when present, is what lets the PR trigger `consumed-files`
           # (see the header). `persist-credentials` keeps it for the push.
           token: ${{ secrets.QUANTECON_SERVICES_PAT || github.token }}
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       - run: pip install -r requirements.txt

.github/workflows/validate-datasets.yml

@@ -42,10 +42,10 @@ jobs:
         pandas: ["2.3.3", "3.0.5"]
     name: validate (pandas ${{ matrix.pandas }})
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           lfs: false          # lectures/ is plain git; a pointer here should fail (see consumed-file-check.yml)
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v7
         with:
           python-version: "3.12"
       # wbgapi: builders/business_cycle.py imports it at module level, and the