build(deps): bump slash from 1.12.0 to 1.15.0

Bumps [slash](https://github.com/getslash/slash) from 1.12.0 to 1.15.0.
- [Release notes](https://github.com/getslash/slash/releases)
- [Changelog](https://github.com/getslash/slash/blob/develop/doc/changelog.rst)
- [Commits](getslash/slash@1.12.0...1.15.0)

---
updated-dependencies:
- dependency-name: slash
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -1,4 +1,4 @@
-slash == 1.12.0
+slash == 1.15.0
 numpy == 2.0.0
 scikit-image == 0.24.0
 distro == 1.9.0