add github workflow

.github/workflows/build.yml

@@ -0,0 +1,40 @@
+name: "Build PHP docker image with xdebug module."
+on:
+  push:
+  pull_request:
+  schedule:
+    # https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#schedule
+    # every tuesday(2) at 06:32 UTC (chosen randomly)
+    # Minute[0,59] Hour[0,23] DOM[1,31] MOY[1,12] DOW[0,6]
+    - cron: '32 6 * * 2'
+
+  workflow_dispatch:
+
+permissions:
+  contents: "read"
+
+jobs:
+  docker:
+    runs-on: "ubuntu-latest"
+    strategy:
+      matrix:
+        php-version:
+          - "8.1"
+          - "8.2"
+          - "8.3"
+    steps:
+      - name: "Set up QEMU"
+        uses: "docker/setup-qemu-action@v2"
+      - name: "Set up Docker Buildx"
+        uses: "docker/setup-buildx-action@v2"
+      - name: "Login to Docker Hub"
+        uses: "docker/login-action@v2"
+        with:
+          username: "${{ secrets.DOCKERHUB_USERNAME }}"
+          password: "${{ secrets.DOCKERHUB_TOKEN }}"
+      - name: "Build PHP ${{ matrix.php-version }}"
+        uses: "docker/build-push-action@v4"
+        with:
+          build-args: "PHP_VERSION=${{ matrix.php-version }}-cli"
+          push: true
+          tags: "${{ secrets.DOCKERHUB_USERNAME }}/php-xdebug:${{ matrix.php-version }}"