Add grpc gem

Author: sarahchen6

appraisal/jruby-9.2.rb

@@ -234,7 +234,7 @@
 appraise 'contrib' do
   gem 'concurrent-ruby'
   gem 'i18n', '1.8.7', platform: :jruby # Removal pending: https://github.com/ruby-i18n/i18n/issues/555#issuecomment-772112169
-
+  gem 'grpc'
   gem 'rack-test' # Dev dependencies for testing rack-based code
   gem 'rake', '>= 12.3'
   gem 'resque'

appraisal/jruby-9.3.rb

@@ -206,7 +206,7 @@
 
 appraise 'contrib' do
   gem 'concurrent-ruby'
-
+  gem 'grpc'
   gem 'rack-test' # Dev dependencies for testing rack-based code
   gem 'rake', '>= 12.3'
   gem 'redis', '~> 4'

appraisal/jruby-9.4.rb

@@ -116,7 +116,7 @@
 
 appraise 'contrib' do
   gem 'concurrent-ruby'
-
+  gem 'grpc'
   gem 'rack-test' # Dev dependencies for testing rack-based code
   gem 'rake', '>= 12.3'
   gem 'resque'