Add github action to test code targeted to main branch

Author: ooade

.github/workflows/build-test-code.yml

@@ -0,0 +1,17 @@
+name: Test code on pull request
+
+on:
+	pull_request:
+		branches: [main]
+
+jobs:
+	test_pull_request:
+		runs-on: ubuntu-latest
+		steps:
+			- uses: actions/checkout@v2
+			- uses: actions/setup-node@v1
+				with:
+					node-version: 12
+      - run: npm ci
+      - run: npm test
+      - run: npm run build