Update gem-push.yml

Author: highb

.github/workflows/gem-push.yml

@@ -16,10 +16,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Ruby 2.7
+    - name: Set up Ruby 3.0
       uses: ruby/setup-ruby@473e4d8fe5dd94ee328fdfca9f8c9c7afc9dae5e
       with:
-        ruby-version: '2.7'
+        ruby-version: '3.0'
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
     - name: Generate man page