Bump spleeter from 2.3.2 to 2.4.0

Bumps [spleeter](https://github.com/deezer/spleeter) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/deezer/spleeter/releases)
- [Changelog](https://github.com/deezer/spleeter/blob/master/CHANGELOG.md)
- [Commits](https://github.com/deezer/spleeter/commits)

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

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

Author: dependabot[bot]

requirements-spleeter.txt

@@ -1 +1 @@
-spleeter==2.3.2
+spleeter==2.4.0