Bump simple-git and serverless

Bumps [simple-git](https://github.com/steveukx/git-js/tree/HEAD/simple-git) to 3.15.0 and updates ancestor dependency [serverless](https://github.com/serverless/serverless). These dependencies need to be updated together.


Updates `simple-git` from 2.48.0 to 3.15.0
- [Release notes](https://github.com/steveukx/git-js/releases)
- [Changelog](https://github.com/steveukx/git-js/blob/main/simple-git/CHANGELOG.md)
- [Commits](https://github.com/steveukx/git-js/commits/simple-git@3.15.0/simple-git)

Updates `serverless` from 2.69.1 to 3.24.1
- [Release notes](https://github.com/serverless/serverless/releases)
- [Changelog](https://github.com/serverless/serverless/blob/main/CHANGELOG.md)
- [Commits](serverless/serverless@v2.69.1...v3.24.1)

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

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

Author: dependabot[bot]