chore: add workflow to test pull requests if they built

Author: isqua

.github/workflows/main.yml

@@ -0,0 +1,21 @@
+name: Main
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test-build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: .nvmrc
+          cache: npm
+          cache-dependency-path: package-lock.json
+      - name: Install dependencies
+        run: npm install
+      - name: Build website
+        run: npm run build