Merge pull request #15173 from backstage/jhaals/next-micro

microsite-next: Add experimental microsite with CI workflow

.github/vale/Vocab/Backstage/accept.txt

@@ -411,3 +411,6 @@ zoomable
 zsh
 Lainfiesta
 allowlisted
+Dominik
+Henneke
+Kuang

.github/workflows/verify_microsite-next.yml

@@ -0,0 +1,44 @@
+name: Verify Microsite Next
+on:
+  pull_request:
+    paths:
+      - '.github/workflows/verify_microsite-next.yml'
+      - 'microsite-next/**'
+      - 'docs/**'
+
+jobs:
+  build-microsite:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [16.x]
+
+    env:
+      CI: true
+      NODE_OPTIONS: --max-old-space-size=4096
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: use node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node-version }}
+
+        # Skip caching of microsite dependencies, it keeps the global cache size
+        # smaller, which make Windows builds a lot faster for the rest of the project.
+      - name: yarn install
+        run: yarn install --immutable
+        working-directory: microsite-next
+
+      - name: verify yarn dependency duplicates
+        run: node scripts/verify-lockfile-duplicates.js
+
+      - name: prettier
+        run: yarn prettier:check
+        working-directory: microsite-next
+
+      - name: build microsite-next
+        run: yarn build
+        working-directory: microsite-next