ci: correctly build and push ci image

.gitea/workflows/build-ci-image.yaml

@@ -4,6 +4,7 @@ on:
   push:
     paths:
       - "Dockerfile.ci"
+      - ".gitea/workflows/build-ci-image.yaml"
 
 jobs:
   build-and-push:
@@ -12,12 +13,20 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Set up Docker BuildX
+        uses: docker/setup-buildx-action@v2
+        with:
+          config-inline: |
+            [registry."git.max-richter.dev"]
+              https = true
+              insecure = false
+
       - name: Login to Gitea Registry
         uses: docker/login-action@v3
         with:
           registry: git.max-richter.dev
           username: ${{ gitea.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
 
       - name: Build and Push
         uses: docker/build-push-action@v5