Update bit-set requirement from 0.5.2 to 0.6.0

Updates the requirements on [bit-set](https://github.com/contain-rs/bit-set) to permit the latest version.
- [Release notes](https://github.com/contain-rs/bit-set/releases)
- [Commits](https://github.com/contain-rs/bit-set/commits)

---
updated-dependencies:
- dependency-name: bit-set
  dependency-type: direct:production
...

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

Author: dependabot[bot]

proptest/Cargo.toml

@@ -82,7 +82,7 @@ version = "0.8"
 optional = true
 
 [dependencies.bit-set]
-version = "0.5.2"
+version = "0.6.0"
 optional = true
 
 [dependencies.bit-vec]