chore(deps-dev): bump mocha from 2.4.0 to 2.4.1 in /fluent-plugin-events

Bumps [mocha](https://github.com/freerange/mocha) from 2.4.0 to 2.4.1.
- [Changelog](https://github.com/freerange/mocha/blob/main/RELEASE.md)
- [Commits](freerange/mocha@v2.4.0...v2.4.1)

---
updated-dependencies:
- dependency-name: mocha
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

fluent-plugin-events/Gemfile.lock

@@ -82,7 +82,7 @@ GEM
     http-parser (1.2.3)
       ffi-compiler (>= 1.0, < 2.0)
     http_parser.rb (0.8.0)
-    mocha (2.4.0)
+    mocha (2.4.1)
       ruby2_keywords (>= 0.0.5)
     msgpack (1.5.1)
     multipart-post (2.4.1)