ci: add github actions pipeline

Author: jokroese

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'pnpm'
+      - name: Install deps
+        run: pnpm install
+      - name: Lint + typecheck + build + test
+        run: pnpm lint && pnpm check && pnpm build && pnpm test