Bump borgmatic from 1.8.7 to 1.8.8

Bumps [borgmatic](https://github.com/borgmatic-collective/borgmatic) from 1.8.7 to 1.8.8.
- [Release notes](https://github.com/borgmatic-collective/borgmatic/releases)
- [Changelog](https://github.com/borgmatic-collective/borgmatic/blob/main/NEWS)
- [Commits](https://github.com/borgmatic-collective/borgmatic/compare/1.8.7...1.8.8)

---
updated-dependencies:
- dependency-name: borgmatic
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements.txt

@@ -2,5 +2,5 @@
 
 apprise==1.7.2
 borgbackup==1.2.7
-borgmatic==1.8.7
+borgmatic==1.8.8
 llfuse==1.5.0