build(deps): Bump github.com/DeRuina/timberjack from 1.4.7 to 1.4.8

Bumps [github.com/DeRuina/timberjack](https://github.com/DeRuina/timberjack) from 1.4.7 to 1.4.8.
- [Release notes](https://github.com/DeRuina/timberjack/releases)
- [Changelog](https://github.com/DeRuina/timberjack/blob/main/CHANGELOG.md)
- [Commits](https://github.com/DeRuina/timberjack/compare/v1.4.7...v1.4.8)

---
updated-dependencies:
- dependency-name: github.com/DeRuina/timberjack
  dependency-version: 1.4.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

go.mod

@@ -1,7 +1,7 @@
 module github.com/decke/smtprelay
 
 require (
-	github.com/DeRuina/timberjack v1.4.7
+	github.com/DeRuina/timberjack v1.4.8
 	github.com/chrj/smtpd v1.0.1
 	github.com/fsnotify/fsnotify v1.10.1
 	github.com/google/uuid v1.6.0