Add GitHub CI script

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: Build & test
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "*"
+    tags-ignore:
+      - "*"
+
+jobs:
+  main:
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/checkout@v3
+    - run: npm install
+    - name: Build & Typecheck
+      run: npm run build
+    - name: Lint
+      run: npm run lint