Actually compile the package before publishing

Without this, the uploaded package is almost empty.

Author: robertknight

.github/workflows/npm-publish.yml

@@ -16,6 +16,8 @@ jobs:
         registry-url: 'https://registry.npmjs.org'
     - name: Install
       run: yarn install --immutable
+    - name: Build
+      run: yarn build
     - name: Publish package
       run: npm publish --access public
       env: