Update which requirement from 4.4 to 6.0 (#2172)

Updates the requirements on [which](https://github.com/harryfei/which-rs) to permit the latest version.
- [Release notes](https://github.com/harryfei/which-rs/releases)
- [Changelog](https://github.com/harryfei/which-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/harryfei/which-rs/compare/4.4.0...6.0.1)

---
updated-dependencies:
- dependency-name: which
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Dominik Maier <domenukk@gmail.com>

libafl_cc/Cargo.toml

@@ -15,7 +15,7 @@ categories = ["development-tools::testing", "emulators", "embedded", "os", "no-s
 
 [build-dependencies]
 cc = { version = "1.0", features = ["parallel"] }
-which = "4.4"
+which = "6.0"
 
 [target.'cfg(target_vendor = "apple")'.build-dependencies]
 glob = "0.3"

libafl_concolic/symcc_libafl/Cargo.toml

@@ -24,6 +24,6 @@ build = ["which", "cmake"]
 clone = ["which"]
 
 [dependencies]
-which = { version = "4.4", optional = true }
+which = { version = "6.0", optional = true }
 cmake = { version = "0.1", optional = true }
 log = "0.4.20"

libafl_concolic/symcc_runtime/Cargo.toml

@@ -32,5 +32,5 @@ libafl_bolts = { path = "../../libafl_bolts", version = "0.12.0", default-featur
 cmake = "0.1"
 bindgen = "0.69.4"
 regex = "1"
-which = "4.4"
+which = "6.0"
 symcc_libafl = { path = "../symcc_libafl", version = "0.12.0" }