Bump libcst from 1.5.1 to 1.6.0

Bumps [libcst](https://github.com/Instagram/LibCST) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/Instagram/LibCST/releases)
- [Changelog](https://github.com/Instagram/LibCST/blob/main/CHANGELOG.md)
- [Commits](Instagram/LibCST@v1.5.1...v1.6.0)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 highlighter==0.2.0
 imperfect==0.3.0
-LibCST==1.5.1
+LibCST==1.6.0
 tomlkit==0.13.2
 pkginfo==1.11.2