Update build action to create docker tag on PRs

.github/workflows/build.yml

@@ -4,22 +4,34 @@ name: Build
 on:
   release:
     types: [published]
+  pull_request:
 
 jobs:
   docker-image:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
 
-      - name: Extract tag name
-        id: vars
-        run: echo "tag=${GITHUB_REF#refs/*/}" >> $GITHUB_OUTPUT
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
 
-      - name: Build and publish docker image
-        uses: docker/build-push-action@v1.1.1
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
         with:
-          repository: faforever/faf-python-server
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
-          build_args: GITHUB_REF=${{ steps.vars.outputs.tag }}
-          tag_with_ref: true
+
+      - name: Docker tag
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: faforever/faf-python-server
+          tags:
+            type=ref,event=tag
+            type=ref,event=pr
+
+      - name: Build and publish docker image
+        uses: docker/build-push-action@v6
+        with:
+          build-args: GITHUB_REF=${{ github.event_name == 'release' && github.ref_name || github.head_ref }}
+          tags: ${{ steps.meta.outputs.tags }}