build: Bump itoa from 1.0.5 to 1.0.6 in /fuzz

Bumps [itoa](https://github.com/dtolnay/itoa) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/dtolnay/itoa/releases)
- [Commits](https://github.com/dtolnay/itoa/compare/1.0.5...1.0.6)

---
updated-dependencies:
- dependency-name: itoa
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

fuzz/Cargo.lock

@@ -351,9 +351,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "1.0.5"
+version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fad582f4b9e86b6caa621cabeb0963332d92eea04729ab12892c2533951e6440"
+checksum = "453ad9f582a441959e5f0d088b02ce04cfe8d51a8eaf077f12ac6d3e94164ca6"
 
 [[package]]
 name = "jobserver"