Ignore npmjs links in check links CI job (#943)

Author: mfisher87

.github/workflows/build.yml

@@ -239,7 +239,7 @@ jobs:
       - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       - uses: jupyterlab/maintainer-tools/.github/actions/check-links@v1
         with:
-          ignore_links: 'lite/'
+          ignore_links: 'lite/ https://www.npmjs.com.*'
 
   build-lite:
     name: Build JupyterLite artifacts