feat: publish Docker image on GitHub

.github/workflows/publish_image.yaml

@@ -0,0 +1,40 @@
+name: Publish example-restapi image
+on:
+  push:
+    branches:
+      - main
+env:
+  REGISTRY: ghcr.io
+  XROAD_HOME: ${{ github.workspace }}
+jobs:
+  Publish:
+    name: Publish example-restapi image
+    runs-on: ubuntu-22.04
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: ${{ github.workspace }}
+          push: true
+          tags: ghcr.io/nordic-institute/xrddev-example-restapi:latest
+      - name: Clean old images
+        uses: snok/container-retention-policy@v2
+        with:
+          image-names: xrddev-example-restapi
+          cut-off: 1 week ago UTC
+          timestamp-to-use: created_at
+          account-type: org
+          org-name: nordic-institute
+          keep-at-least: 1
+          token-type: github-token
+          token: ${{ secrets.GITHUB_TOKEN }}