update ruby version to 3.0.2

Author: tashirosota

.github/workflows/ruby.yml

@@ -26,7 +26,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby-version: ['2.5', '2.6', '2.7', '3.0.1']
+        ruby-version: ['2.5', '2.6', '2.7', '3.0.2']
         gemfile:
           - Gemfile
           - Gemfile.rails60