Explicitly set NPM registry URL

Otherwise the action doesn't configure npm properly to authenticate and
our publish actions will fail with 404 errors.

.github/workflows/deploy.yml

@@ -10,6 +10,9 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v1
+        with:
+          # Needs to be explicitly specified for auth to work
+          registry-url: 'https://registry.npmjs.org'
       - run: npm install
       - run: npm publish --access public
         env: