Bump karma-coverage-istanbul-reporter from 1.4.2 to 2.1.0

Bumps [karma-coverage-istanbul-reporter](https://github.com/mattlewis92/karma-coverage-istanbul-reporter) from 1.4.2 to 2.1.0.
- [Release notes](https://github.com/mattlewis92/karma-coverage-istanbul-reporter/releases)
- [Changelog](https://github.com/mattlewis92/karma-coverage-istanbul-reporter/blob/master/CHANGELOG.md)
- [Commits](mattlewis92/karma-coverage-istanbul-reporter@v1.4.2...v2.1.0)

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

Author: dependabot-preview[bot]