fine, I'll do it myself

.gitea/workflows/build-docker.yml

@@ -0,0 +1,49 @@
+name: Build Container
+run-name: ${{ gitea.actor }} is pushing
+on:
+  push:
+    tags:
+      - "v*.*.*"
+
+env:
+  REGISTRY: gitea.haschek.at
+  IMAGE_NAME: ${{ gitea.repository }}
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "🎉 Building ${{ gitea.repository }} because of a ${{ gitea.event_name }} event."
+
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha          
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.BUILD_TOKEN}}
+
+      - name: Build
+        uses: docker/build-push-action@v3
+        env:
+          ACTIONS_RUNTIME_TOKEN: ''
+        with:
+          context: .
+          file: docker/Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+