Update afl requirement from 0.14.5 to 0.15.2

Updates the requirements on [afl](https://github.com/rust-fuzz/afl.rs) to permit the latest version.
- [Changelog](https://github.com/rust-fuzz/afl.rs/blob/master/CHANGES.md)
- [Commits](https://github.com/rust-fuzz/afl.rs/commits)

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

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

fuzzer/Cargo.toml

@@ -11,5 +11,5 @@ exclude = ["target", "Cargo.lock"]
 publish = false
 
 [dependencies]
-afl = "0.14.5"
+afl = "0.15.2"
 anes = { path = "../anes", features = ["parser"] }