[Chore] Add CI step to validate and update OpenAPI spec (alexjustesen#2222)

Co-authored-by: Alex Justesen <[email protected]>

Author: svenvg93

.github/workflows/update-openapi.yml

@@ -0,0 +1,40 @@
+name: Update OpenAPI JSON
+
+on:
+  push:
+    paths:
+      - 'app/Http/Controllers/Api/**/*.php'
+      - 'app/OpenApi/**/*.php'
+
+jobs:
+  update-openapi:
+    runs-on: ubuntu-24.04
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+      with:
+        ref: ${{ github.event.pull_request.head.ref }}
+        repository: ${{ github.event.pull_request.head.repo.full_name }}
+
+    - name: Set up PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: '8.3'
+
+    - name: Install dependencies
+      run: composer install -q --no-ansi --no-interaction --no-scripts --no-progress
+
+    - name: Generate OpenAPI JSON
+      run: ./vendor/bin/openapi app -o openapi_temp.json -f json
+
+    - name: Commit OpenAPI JSON if changed
+      run: |
+        if ! diff -q openapi.json openapi_temp.json; then
+          mv openapi_temp.json openapi.json
+          git config user.name "GitHub Action"
+          git config user.email "[email protected]"
+          git add openapi.json
+          git commit -m "Update OpenAPI JSON"
+          git push
+        fi