build: Bump itoa from 1.0.3 to 1.0.4 in /fuzz

Bumps [itoa](https://github.com/dtolnay/itoa) from 1.0.3 to 1.0.4.
- [Release notes](https://github.com/dtolnay/itoa/releases)
- [Commits](https://github.com/dtolnay/itoa/compare/1.0.3...1.0.4)

---
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

@@ -388,9 +388,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c8af84674fe1f223a982c933a0ee1086ac4d4052aa0fb8060c12c6ad838e754"
+checksum = "4217ad341ebadf8d8e724e264f13e593e0648f5b3e94b3896a5df283be015ecc"
 
 [[package]]
 name = "jobserver"