Add PR build workflow (#4)

* Add PR build workflow

* Change build context

* Fix context

.github/workflows/build.yml

@@ -0,0 +1,31 @@
+name: gci-e2e
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [master]
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - name: Checkout bgutil-ytdlp-pot-provider
+        uses: actions/checkout@v4
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+      - name: Build Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: server/
+          file: server/Dockerfile
+          push: false
+          tags: brainicism/bgutil-ytdlp-pot-provider:ci