Bump webmock from 3.8.3 to 3.9.1 (#14780)

Bumps [webmock](https://github.com/bblimke/webmock) from 3.8.3 to 3.9.1.
- [Release notes](https://github.com/bblimke/webmock/releases)
- [Changelog](https://github.com/bblimke/webmock/blob/master/CHANGELOG.md)
- [Commits](https://github.com/bblimke/webmock/compare/v3.8.3...v3.9.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile

@@ -126,7 +126,7 @@ group :test do
   gem 'rails-controller-testing', '~> 1.0'
   gem 'rspec-sidekiq', '~> 3.1'
   gem 'simplecov', '~> 0.19', require: false
-  gem 'webmock', '~> 3.8'
+  gem 'webmock', '~> 3.9'
   gem 'parallel_tests', '~> 3.2'
   gem 'rspec_junit_formatter', '~> 0.4'
 end