Bump karma from 6.3.18 to 6.3.20 (#5241)

Bumps [karma](https://github.com/karma-runner/karma) from 6.3.18 to 6.3.20.
- [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/v6.3.18...v6.3.20)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: John Hill <john.c.hill@nasa.gov>

package.json

@@ -37,7 +37,7 @@
     "imports-loader": "0.8.0",
     "jasmine-core": "4.1.1",
     "jsdoc": "3.5.5",
-    "karma": "6.3.18",
+    "karma": "6.3.20",
     "karma-chrome-launcher": "3.1.1",
     "karma-cli": "2.0.0",
     "karma-coverage": "2.2.0",