ci: change CI to publish to GitHub package registry

* Use github npm registry.

* We can use the GITHUB_TOKEN that is made available by default in a
  GitHub Action as the NODE_AUTH_TOKEN, although we need to add the
`packages: write` permission to the Action.

Co-authored-by: Chris Roos <[email protected]>
Co-authored-by: Chris Lowis <[email protected]>

Author: 3 people

.github/workflows/publish.yml

@@ -59,7 +59,7 @@ jobs:
         with:
           cache: 'npm'
           node-version-file: '.nvmrc'
-          registry-url: 'https://registry.npmjs.org'
+          registry-url: "https://npm.pkg.github.com"
 
       - uses: ./.github/actions/install-dependencies
 
@@ -82,7 +82,7 @@ jobs:
       - name: Publish scratch-gui
         run: npm publish --access=public --tag="${{steps.npm_tag.outputs.npm_tag}}" --workspace=@scratch/scratch-gui
         env:
-          NODE_AUTH_TOKEN: ${{secrets.NPM_TOKEN}}
+          NODE_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}
 
       - name: Push to develop
         shell: bash