ci: auto increase build number on pull requests (#17)

.github/workflows/increase-build-number.yaml

@@ -0,0 +1,35 @@
+name: Increase build number on pull request
+
+on:
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: write
+
+jobs:
+  increase-build-number:
+    if: !startsWith(github.event.pull_request.title, 'ci:')
+    name: Increase build number
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+
+      - name: Increase build number
+        id: increase-build-number
+        run: |
+          buildNumber=$(grep buildNumber= build-number.properties | cut -d'=' -f2)
+          buildNumber=$((buildNumber+1))
+          sed -i "s/buildNumber=.*/buildNumber=$buildNumber/" build-number.properties
+          echo "buildNumber=$buildNumber" >> $GITHUB_OUTPUT
+
+      - name: Commit and push changes
+        run: |
+          git config user.name github-actions
+          git add build-number.properties
+          git commit -m "chore: increase build number to ${{ steps.increase-build-number.outputs.buildNumber }}"
+          git push