Add CI testing matrix

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+name: Run Tests
+on:
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  tests:
+    strategy:
+      matrix:
+        node: [18, 20, 22]
+        os: [ubuntu-latest, windows-latest]
+
+    runs-on: ${{ matrix.os }}
+    name: Run Tests on Node v${{ matrix.node }}
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: 'npm'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: >
+          cd packages/tailwindcss-language-server &&
+          npm run build &&
+          npm run test:prepare &&
+          npm test