gitlab: 11.10.8 -> 12.0.3

This is a major version bump but things were generally straightforward
save two wrinkles:

 * it is necessary to ignore collisions in the gitlab bundler
   environment as both `omniauth_oauth2_generic` and
   `apollo_upload_server` provide a `console` executable.

 * grpc had to be patched since its build system expects the `AR`
   environment variable to contain not just the path to `ar` but
   also the `rpc` flags (see the discussion in nixpkgs #63056).

pkgs/applications/version-management/gitlab/fix-grpc-ar.patch

@@ -0,0 +1,10 @@
+--- a/src/ruby/ext/grpc/extconf.rb
++++ b/src/ruby/ext/grpc/extconf.rb
+@@ -27,6 +27,7 @@ ENV['MACOSX_DEPLOYMENT_TARGET'] = '10.7'
+ if ENV['AR'].nil? || ENV['AR'].size == 0
+     ENV['AR'] = RbConfig::CONFIG['AR'] + ' rcs'
+ end
++ENV['AR'] = ENV['AR'] + ' rcs'
+ if ENV['CC'].nil? || ENV['CC'].size == 0
+     ENV['CC'] = RbConfig::CONFIG['CC']
+ end