chore: Upgrade rails and ruby versions (#2400)

ruby version: 3.0.2
rails version: 6.1.4

Gemfile

@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-ruby '2.7.3'
+ruby '3.0.2'
 
 ##-- base gems for rails --##
 gem 'rack-cors', require: 'rack/cors'
@@ -40,7 +40,7 @@ gem 'rack-attack'
 gem 'aws-sdk-s3', require: false
 gem 'azure-storage-blob', require: false
 gem 'google-cloud-storage', require: false
-gem 'mini_magick'
+gem 'image_processing'
 
 ##-- gems for database --#
 gem 'groupdate'
@@ -91,8 +91,11 @@ gem 'google-cloud-dialogflow'
 ##--- gems for debugging and error reporting ---##
 # static analysis
 gem 'brakeman'
+gem 'ddtrace'
 gem 'scout_apm'
-gem 'sentry-raven'
+gem 'sentry-rails'
+gem 'sentry-ruby'
+gem 'sentry-sidekiq'
 
 ##-- background job processing --##
 gem 'sidekiq'
@@ -121,7 +124,7 @@ group :development do
   gem 'web-console'
 
   # used in swagger build
-  gem 'json_refs', git: 'https://github.com/tzmfreedom/json_refs', ref: '131b11294fd6af9c428171f38516e6222a58c874'
+  gem 'json_refs'
 
   # When we want to squash migrations
   gem 'squasher'
@@ -135,19 +138,19 @@ group :test do
 end
 
 group :development, :test do
+  gem 'active_record_query_trace'
   gem 'bundle-audit', require: false
   gem 'byebug', platform: :mri
   gem 'factory_bot_rails'
   gem 'faker'
   gem 'listen'
-  gem 'mock_redis', git: 'https://github.com/sds/mock_redis', ref: '16d00789f0341a3aac35126c0ffe97a596753ff9'
+  gem 'mock_redis'
   gem 'pry-rails'
-  gem 'rspec-rails', '~> 4.0.0.beta2'
+  gem 'rspec-rails', '~> 5.0.0'
   gem 'rubocop', require: false
   gem 'rubocop-performance', require: false
   gem 'rubocop-rails', require: false
   gem 'rubocop-rspec', require: false
-  gem 'scss_lint', require: false
   gem 'seed_dump'
   gem 'shoulda-matchers'
   gem 'simplecov', '0.17.1', require: false