Merge pull request #89 from tbetbetbe/grpc_ruby_upgrade_protobuf_ruby_again

Fixes a regression in the style pull request

src/ruby/grpc.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'xray'
   s.add_dependency 'logging', '~> 1.8'
-  s.add_dependency 'google-protobuf', '~> 3.0.0alpha'
+  s.add_dependency 'google-protobuf', '~> 3.0.0alpha.1.1'
   s.add_dependency 'minitest', '~> 5.4'  # reqd for interop tests
 
   s.add_development_dependency 'bundler', '~> 1.7'