build(deps): bump simple-git in /examples/serverless-localstack

Bumps [simple-git](https://github.com/steveukx/git-js/tree/HEAD/simple-git) from 3.7.1 to 3.15.1.
- [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@3.15.1/simple-git)

---
updated-dependencies:
- dependency-name: simple-git
  dependency-type: indirect
...

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Author: dependabot[bot]