Update publish.yml

Author: auchenberg

.github/workflows/publish.yml

@@ -11,6 +11,17 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+      
+    - name: Use Node.js ${{ env.NODE_VERSION }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ env.NODE_VERSION }}      
+
+    - name: npm install, build, and test
+      run: |
+        npm install
+        npm run build --if-present
+        npm run test --if-present
     - uses: author/action-publish@stable
       env:
         # Typically an npm token