Setup buildx

.gitea/workflows/docker.yaml

@@ -20,6 +20,8 @@ jobs:
         id: set-tag
         run: |
           echo "TAG_SLUG=${GITHUB_REF_NAME}-${GITHUB_SHA:0:7}-$(date +%s)" >> "$GITHUB_OUTPUT"
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
       - name: Build and push
         id: docker_build
         uses: docker/build-push-action@v4