build(deps): bump .git_submodules/sweet-theme

Bumps [.git_submodules/sweet-theme](https://github.com/EliverLara/Sweet) from `b1d07d9` to `a9a6fcf`.
- [Release notes](https://github.com/EliverLara/Sweet/releases)
- [Commits](EliverLara/Sweet@b1d07d9...a9a6fcf)

---
updated-dependencies:
- dependency-name: ".git_submodules/sweet-theme"
  dependency-type: direct:production
...

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