build(deps): bump packaging/linux/flatpak/deps/flatpak-builder-tools

Bumps [packaging/linux/flatpak/deps/flatpak-builder-tools](https://github.com/flatpak/flatpak-builder-tools) from `9a48b5e` to `6f611f1`.
- [Commits](flatpak/flatpak-builder-tools@9a48b5e...6f611f1)

---
updated-dependencies:
- dependency-name: packaging/linux/flatpak/deps/flatpak-builder-tools
  dependency-type: direct:production
...

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