Bump karma from 6.3.12 to 6.3.15

Bumps [karma](https://github.com/karma-runner/karma) from 6.3.12 to 6.3.15.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](https://github.com/karma-runner/karma/compare/v6.3.12...v6.3.15)

---
updated-dependencies:
- dependency-name: karma
  dependency-type: direct:development
  update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>

yarn.lock

@@ -4781,9 +4781,9 @@ karma-source-map-support@^1.4.0:
     source-map-support "^0.5.5"
 
 karma@^6.0.1:
-  version "6.3.12"
-  resolved "https://registry.yarnpkg.com/karma/-/karma-6.3.12.tgz#fe6347f027385fc16da1a9bb87d766e2d25981c6"
-  integrity sha512-qwIG+oB2YmHx4hjvYSRMNzL3YWAJ9baHaLAxiP7biFNkfpwYTUTtPck0joFpucalNLzMr+7z/FX1uY/kl8DV9A==
+  version "6.3.15"
+  resolved "https://registry.yarnpkg.com/karma/-/karma-6.3.15.tgz#6c3beedb2440b05589a502462140afed724481e7"
+  integrity sha512-4O5X6zVFdmwo/fgjRN84fPG3IvaiOxOjIeZBwBrQYz4nIyGqlF8Wm7C1Hr7idQ9NHgnvJM+LSjZwS1C+qALMGw==
   dependencies:
     body-parser "^1.19.0"
     braces "^3.0.2"
@@ -4797,9 +4797,10 @@ karma@^6.0.1:
     http-proxy "^1.18.1"
     isbinaryfile "^4.0.8"
     lodash "^4.17.21"
-    log4js "^6.3.0"
+    log4js "^6.4.1"
     mime "^2.5.2"
     minimatch "^3.0.4"
+    mkdirp "^0.5.5"
     qjobs "^1.2.0"
     range-parser "^1.2.1"
     rimraf "^3.0.2"
@@ -5001,10 +5002,10 @@ log-symbols@^2.1.0:
   dependencies:
     chalk "^2.0.1"
 
-log4js@^6.3.0:
-  version "6.4.0"
-  resolved "https://registry.yarnpkg.com/log4js/-/log4js-6.4.0.tgz#3f63ccfc8033c83cd617a4d2d50e48be5944eae9"
-  integrity sha512-ysc/XUecZJuN8NoKOssk3V0cQ29xY4fra6fnigZa5VwxFsCsvdqsdnEuAxNN89LlHpbE4KUD3zGcn+kFqonSVQ==
+log4js@^6.4.1:
+  version "6.4.1"
+  resolved "https://registry.yarnpkg.com/log4js/-/log4js-6.4.1.tgz#9d3a8bf2c31c1e213fe3fc398a6053f7a2bc53e8"
+  integrity sha512-iUiYnXqAmNKiIZ1XSAitQ4TmNs8CdZYTAWINARF3LjnsLN8tY5m0vRwd6uuWj/yNY0YHxeZodnbmxKFUOM2rMg==
   dependencies:
     date-format "^4.0.3"
     debug "^4.3.3"