chore: Upgrade rails and ruby versions (#2400)

ruby version: 3.0.2
rails version: 6.1.4

.circleci/config.yml

@@ -7,7 +7,7 @@ defaults: &defaults
   working_directory: ~/build
   docker:
     # specify the version you desire here
-    - image: circleci/ruby:2.7.3-node-browsers
+    - image: circleci/ruby:3.0.2-node-browsers
 
     # Specify service dependencies here if necessary
     # CircleCI maintains a library of pre-built images