Add Javascript update Github Actions workflow (#275)

* JS update workflow

* Update package.json to see if workflow fires properly

* Commit updated Javascript packages

Co-authored-by: Owncast <owncast@owncast.online>

.github/workflows/javascript-packages.yaml

@@ -0,0 +1,28 @@
+name: javascript-packages
+on:
+  push:
+    paths:
+      - build/javascript/package.json
+
+jobs:
+  run:
+    name: npm run build
+    runs-on: ubuntu-latest
+    steps:
+        - name: Checkout repo
+          uses: actions/checkout@v2
+
+        - name: Install dependencies
+          run: |
+            cd build/javascript
+            npm run build
+
+        - name: Commit changes
+          uses: EndBug/add-and-commit@v5
+          with:
+            author_name: Owncast
+            author_email: owncast@owncast.online
+            message: "Commit updated Javascript packages"
+            add: "build/javascript/package* webroot/js/web_modules"
+          env:
+            GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}