Bump webmock in /gemfiles/sidekiq-4.x-graphql-1.7.x

Bumps [webmock](https://github.com/bblimke/webmock) from 3.12.0 to 3.12.1.
- [Release notes](https://github.com/bblimke/webmock/releases)
- [Changelog](https://github.com/bblimke/webmock/blob/master/CHANGELOG.md)
- [Commits](bblimke/webmock@v3.12.0...v3.12.1)

Signed-off-by: dependabot[bot] <support@github.com>

gemfiles/sidekiq-4.x-graphql-1.7.x/Gemfile.lock

@@ -179,7 +179,7 @@ GEM
     tzinfo (1.2.9)
       thread_safe (~> 0.1)
     unicode-display_width (2.0.0)
-    webmock (3.12.0)
+    webmock (3.12.1)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)