Update rubygems/configure-rubygems-credentials action to v2

Author: renovate[bot]

.github/workflows/publish.yml

@@ -54,7 +54,7 @@ jobs:
         run: bundle exec rake package
 
       # Release
-      - uses: rubygems/configure-rubygems-credentials@v1.0.0
+      - uses: rubygems/configure-rubygems-credentials@v2.1.0
       - name: Publish gem
         run: bundle exec rake push:all
       - name: Wait for release