major: first v0.3.0 release PR (#220)

This PR lays the foundation for the next iteration of the library,
`v0.3.0`, as it introduces some breaking changes to the current API.

## Revert to single Go module

In terms of UX, the library reverts back to being a single Go module,
rather than continuing along the path of a monorepo of multiple Go
modules.

This move introduces multiple benefits, such as:

- Easier discoverability of packages within the lib, as they are
imported with the same `go get`,
- Easier experience in development and release of updated, especially
minor dependency updates.

The potential downside of this move is the introduction of more
transient dependencies for consumers; however, the Go compiler already
handles the removal of dependencies in the dependency graph that are not
used/referenced during compilation.

## Minimum version Go 1.21

The library does rely by a pretty good margin on generics, especially
when it comes to the core packages (e.g. `aggregate`, `message`, etc.)

With Go 1.21, the ergonomics around generics usage has increased
considerably, therefore we now target that specific API version.

## More functional constructors

Connected to the previous point, to increase the UX for consumers of the
library, we expect that many of the `struct` components with previously
exported fields will now have _private_ fields and require a functional
constructor, i.e. `func NewComponent()`.

The reason for this change is that generics type inference works much
better on functions than it does on direct `struct` instancing.

Author: ar3s3ru

.github/actions/setup-go/action.yml

@@ -1,29 +1,15 @@
+---
 # To get started with Dependabot version updates, you'll need to specify which
 # package ecosystems to update and where the package manifests are located.
 # Please see the documentation for all configuration options:
 # https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
 
 version: 2
 updates:
-  # Maintain dependencies for Go
   - package-ecosystem: "gomod"
-    directory: "/core"
-    schedule:
-      interval: "weekly"
-  - package-ecosystem: "gomod"
-    directory: "/oteleventually"
-    schedule:
-      interval: "weekly"
-  - package-ecosystem: "gomod"
-    directory: "/postgres"
-    schedule:
-      interval: "weekly"
-  - package-ecosystem: "gomod"
-    directory: "/serdes"
+    directory: "/"
     schedule:
       interval: "weekly"
-
-  # Maintain dependencies for GitHub Actions
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:

.github/actions/setup-golangci-lint/action.yml

@@ -1,18 +1,22 @@
+---
+name: Release
+
 on: workflow_dispatch
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-name: release-please
+permissions: read-all
+
 jobs:
-  release-please:
+  run:
     runs-on: ubuntu-latest
     permissions:
       contents: write
       pull-requests: write
     steps:
-      - name: Release
+      - name: Run release-please
         uses: google-github-actions/release-please-action@v4
         with:
           include-component-in-tag: true

.github/dependabot.yml

@@ -0,0 +1,66 @@
+---
+name: Lint
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+on:  # yamllint disable-line rule:truthy
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+permissions: read-all
+
+jobs:
+  go:
+    name: Go
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@v4
+        with:
+          args: --timeout=5m
+
+  super-linter:
+    name: Super Linter
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: read
+      statuses: write
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+        with:
+          # Full git history is needed to get a proper
+          # list of changed files within `super-linter`
+          fetch-depth: 0
+      - name: Run super-linter
+        uses: super-linter/super-linter@v6
+        env:
+          VALIDATE_ALL_CODEBASE: false
+          DEFAULT_BRANCH: main
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          # Linters are on the top-level of the repository.
+          LINTER_RULES_PATH: ./
+          # Go is made out of copy-paste, forget this one.
+          VALIDATE_JSCPD: false
+          # NOTE: using Buf as linter, which is not supported by SuperLinter.
+          VALIDATE_PROTOBUF: false
+          # NOTE: super-linter has quite poor support for golangci-lint.
+          # We use the official linter action for it instead.
+          VALIDATE_GO: false
+          VALIDATE_GO_MODULES: false

.github/workflows/release-please.yml .github/release.old.yml.github/workflows/release-please.yml renamed to .github/release.old.yml

@@ -0,0 +1,35 @@
+---
+name: Test
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+on:  # yamllint disable-line rule:truthy
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+permissions: read-all
+
+jobs:
+  go:
+    name: Go
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+      - name: Run go test
+        run: make go.test
+      - name: Analyze with SonarCloud
+        uses: sonarsource/sonarcloud-github-action@v2.1
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}

.github/workflows/lint.yml

@@ -1,5 +1,5 @@
-vendor
-*.out
-go.work.sum
-
+# local development environment
 .direnv
+
+# go
+coverage.txt