ci: Add basic GH Actions worfklow to test & build project.

Author: microbit-carlos

.github/workflows/build.yml

@@ -0,0 +1,16 @@
+name: Test & Build
+
+on:
+  push:
+    branches: '*'
+  pull_request:
+    branches: '*'
+
+jobs:
+  test-build:
+    name: Run tests and build project
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: npm ci
+      - run: npm run build