chore(deps): bump simple-git and serverless

Removes [simple-git](https://github.com/steveukx/git-js/tree/HEAD/simple-git). It's no longer used after updating ancestor dependency [serverless](https://github.com/serverless/serverless). These dependencies need to be updated together.


Removes `simple-git`

Updates `serverless` from 2.72.3 to 4.1.21
- [Release notes](https://github.com/serverless/serverless/releases)
- [Changelog](https://github.com/serverless/serverless/blob/main/CHANGELOG.md)
- [Commits](https://github.com/serverless/serverless/commits)

---
updated-dependencies:
- dependency-name: simple-git
  dependency-type: indirect
- dependency-name: serverless
  dependency-type: direct:development
...

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