Add test step to pre-release workflow

Author: bradlc

.github/workflows/pre-release.yml

@@ -19,6 +19,11 @@ jobs:
           key: ${{ runner.os }}-${{ env.NODE_VERSION }}-node_modules-${{ hashFiles('**/package-lock.json') }}
       - name: Install dependencies
         run: npm install && npm run bootstrap
+      - name: Run tests
+        run: >
+          cd packages/tailwindcss-language-server &&
+          npm run build &&
+          npm test
       - name: Bump IntelliSense version
         run: >
           node .github/workflows/bump-version.mjs &&