fixed release build directory for Github action

.github/workflows/build_push_server_release.yml

@@ -149,8 +149,8 @@ jobs:
       - name: Build and push immich-proxy release
         uses: docker/build-push-action@v3.0.0
         with:
-          context: ./web
-          file: ./web/Dockerfile
+          context: ./nginx
+          file: ./nginx/Dockerfile
           platforms: linux/arm/v7,linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: |