chore: use gitea actions to build and publish docker image

.gitea/workflows/build-docker.yaml

@@ -0,0 +1,29 @@
+name: Build and Publish Docker Image
+
+on: [push]
+
+env:
+  REGISTRY: git.sqrt.fr
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    
+    steps:
+      - uses: actions/checkout@v4
+      
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      
+      - name: Log in to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.PACKAGES_TOKEN }}
+      
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          tags: ${{ env.REGISTRY }}/${{ gitea.repository }}:latest