Add Ruby 3.4 to CI

Extend the GitHub Actions test matrices to include Ruby 3.4 while
retaining older supported versions.

Author: evolve75

.github/workflows/coveralls.yml

@@ -21,7 +21,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3"]
+        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
     runs-on: ubuntu-latest
 
     steps:

.github/workflows/ruby.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3"]
+        ruby: ["2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2