added step to build

Author: Tyson Williams

.github/workflows/npm-publish.yml

@@ -15,6 +15,8 @@ jobs:
       uses: actions/setup-node@master
       with:
         node-version: 12.0.0
+    - name: Build the package
+      run: npm run build
     - name: Publish if version has been updated
       uses: pascalgn/npm-publish-action@1.3.3
       with: # Documentation of inputs https://github.com/marketplace/actions/publish-to-npm#inputs