Bumps [babel-plugin-istanbul](https://github.com/istanbuljs/babel-plugin-istanbul) from 5.1.4 to 5.2.0.
- [Release notes](https://github.com/istanbuljs/babel-plugin-istanbul/releases)
- [Changelog](https://github.com/istanbuljs/babel-plugin-istanbul/blob/master/CHANGELOG.md)
- [Commits](https://github.com/istanbuljs/babel-plugin-istanbul/compare/v5.1.4...v5.2.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>