Use gitaly 0.5.0

Gemfile

@@ -352,4 +352,4 @@ gem 'vmstat', '~> 2.3.0'
 gem 'sys-filesystem', '~> 1.1.6'
 # Gitaly GRPC client
-gem 'gitaly', '~> 0.3.0'
+gem 'gitaly', '~> 0.5.0'

Gemfile.lock

@@ -253,7 +253,7 @@ GEM
       json
     get_process_mem (0.2.0)
     gherkin-ruby (0.3.2)
-    gitaly (0.3.0)
+    gitaly (0.5.0)
       google-protobuf (~> 3.1)
       grpc (~> 1.0)
     github-linguist (4.7.6)
@@ -899,7 +899,7 @@ DEPENDENCIES
   fuubar (~> 2.0.0)
   gemnasium-gitlab-service (~> 0.2)
   gemojione (~> 3.0)
-  gitaly (~> 0.3.0)
+  gitaly (~> 0.5.0)
   github-linguist (~> 4.7.0)
   gitlab-flowdock-git-hook (~> 1.0.1)
   gitlab-markup (~> 1.5.1)