chore(ci): implement actionlint for GitHub Actions workflows (#13)

Add actionlint to validate workflow files:
- Add actionlint pre-commit hook (v1.7.10)
- Add actionlint CI workflow
- Fix existing issues in build-phar.yml:
  - Quote $GITHUB_OUTPUT (shellcheck SC2086)
  - Update actions/cache v3 → v4
  - Update softprops/action-gh-release v1 → v2

Fixes #11

Co-authored-by: Claude Opus 4.5 <[email protected]>

Author: kojiromike

.github/workflows/actionlint.yml

@@ -0,0 +1,21 @@
+name: actionlint
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  actionlint:
+    name: Lint GitHub Actions workflows
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Run actionlint
+      uses: rhysd/[email protected]

.github/workflows/build-phar.yml

@@ -30,10 +30,10 @@ jobs:
 
     - name: Get Composer cache directory
       id: composer-cache
-      run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
+      run: echo "dir=$(composer config cache-files-dir)" >> "$GITHUB_OUTPUT"
 
     - name: Cache Composer dependencies
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ steps.composer-cache.outputs.dir }}
         key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
@@ -58,7 +58,7 @@ jobs:
 
     - name: Upload PHAR to release
       if: github.event_name == 'release'
-      uses: softprops/action-gh-release@v1
+      uses: softprops/action-gh-release@v2
       with:
         files: |
           build/oce-import-codes.phar

.pre-commit-config.yaml

@@ -32,6 +32,11 @@ repos:
     - --indent=2
     exclude: ^compose\.yml$  # Uses Docker Compose !override tags
 
+- repo: https://github.com/rhysd/actionlint
+  rev: v1.7.10
+  hooks:
+  - id: actionlint
+
 - repo: local
   hooks:
   - id: php-syntax-check