Add GitHub Action to run tsc on pull request events (#232)

.github/workflows/build_pull_request.yml

@@ -0,0 +1,17 @@
+name: CI Pull Request
+on:
+  pull_request:
+jobs:
+  build:
+    name: ci-pull-request
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install modules
+        run: yarn
+
+      - name: Run ESLint
+        run: yarn lint
+
+      - name: Run TSC
+        run: yarn tsc