CI: Use trusted Gem publishing

Now that Rubygems has support for shared workflows
we can remove the API key and use trusted publishing
instead.

Author: tvdeyen

.github/workflows/release.yml

@@ -18,4 +18,3 @@ jobs:
     secrets:
       app_id: ${{ vars.ALCHEMY_BOT_APP_ID }}
       app_private_key: ${{ secrets.ALCHEMY_BOT_APP_PRIVATE_KEY }}
-      rubygems_api_key: ${{ secrets.RUBYGEMS_API_KEY }}