Bump flat and @rpii/wdio-html-reporter

Bumps [flat](https://github.com/hughsk/flat) to 5.0.2 and updates ancestor dependency [@rpii/wdio-html-reporter](https://github.com/rpii/wdio-html-reporter). These dependencies need to be updated together.


Updates `flat` from 4.1.1 to 5.0.2
- [Commits](hughsk/flat@4.1.1...5.0.2)

Updates `@rpii/wdio-html-reporter` from 6.3.1 to 6.4.0
- [Changelog](https://github.com/rpii/wdio-html-reporter/blob/master/changes.md)
- [Commits](https://github.com/rpii/wdio-html-reporter/commits)

---
updated-dependencies:
- dependency-name: flat
  dependency-type: indirect
- dependency-name: "@rpii/wdio-html-reporter"
  dependency-type: direct:development
...

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

Author: dependabot[bot]