chore: add a build workflow to ensure the Dockerfile is alright

.github/workflows/build.yml

@@ -0,0 +1,19 @@
+name: build.yml
+on:
+  push:
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      -
+        name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          build-args: |
+            MANIFEST_ID="community.webstreamr"
+            MANIFEST_NAME="WebStreamr"
+          push: false
+          tags: webstreamr/webstreamr:latest