Upgrade Gitaly-Proto to 1.37.0

This was done to perform some local testing, but while the change was
already made it made sense to commit the change.

Gemfile

@@ -431,7 +431,7 @@ group :ed25519 do
 end
 # Gitaly GRPC client
-gem 'gitaly-proto', '~> 1.36.0', require: 'gitaly'
+gem 'gitaly-proto', '~> 1.37.0', require: 'gitaly'
 gem 'grpc', '~> 1.19.0'

Gemfile.lock

@@ -310,7 +310,7 @@ GEM
       gettext_i18n_rails (>= 0.7.1)
       po_to_json (>= 1.0.0)
       rails (>= 3.2.0)
-    gitaly-proto (1.36.0)
+    gitaly-proto (1.37.0)
       grpc (~> 1.0)
     github-markup (1.7.0)
     gitlab-labkit (0.3.0)
@@ -1119,7 +1119,7 @@ DEPENDENCIES
   gettext (~> 3.2.2)
   gettext_i18n_rails (~> 1.8.0)
   gettext_i18n_rails_js (~> 1.3)
-  gitaly-proto (~> 1.36.0)
+  gitaly-proto (~> 1.37.0)
   github-markup (~> 1.7.0)
   gitlab-labkit (~> 0.3.0)
   gitlab-markup (~> 1.7.0)

lib/gitlab/gitaly_client/repository_service.rb

@@ -5,7 +5,7 @@ module Gitlab
     class RepositoryService
       include Gitlab::EncodingHelper
-      MAX_MSG_SIZE = 128.kilobytes.freeze
+      MAX_MSG_SIZE = 128.kilobytes
       def initialize(repository)
         @repository = repository