tried again to fix #15 (im gonna crash out)

.gitea/workflows/release-docker.yaml

@@ -27,12 +27,17 @@ jobs:
             --username "${{ secrets.REGISTRY_USER }}" \
             --password-stdin
 
+      - name: Prepare Docker image tags
+        run: |
+          IMAGE_REPO="$(echo "git.miaurizius.de/${{ gitea.repository }}" | tr '[:upper:]' '[:lower:]')"
+          echo "IMAGE_REPO=$IMAGE_REPO" >> "$GITHUB_ENV"
+
       - name: Build and push multi-arch Docker image
         run: |
           docker buildx build \
             --platform linux/amd64,linux/arm64 \
             --file ./Dockerfile \
-            --tag git.miaurizius.de/${{ gitea.repository }}:latest \
-            --tag git.miaurizius.de/${{ gitea.repository }}:${{ gitea.event.release.tag_name }} \
+            --tag "$IMAGE_REPO:latest" \
+            --tag "$IMAGE_REPO:${{ gitea.event.release.tag_name }}" \
             --push \
             .