build: Bump once_cell from 1.14.0 to 1.15.0 in /fuzz

Bumps [once_cell](https://github.com/matklad/once_cell) from 1.14.0 to 1.15.0.
- [Release notes](https://github.com/matklad/once_cell/releases)
- [Changelog](https://github.com/matklad/once_cell/blob/master/CHANGELOG.md)
- [Commits](https://github.com/matklad/once_cell/compare/v1.14.0...v1.15.0)

---
updated-dependencies:
- dependency-name: once_cell
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

fuzz/Cargo.lock

@@ -530,9 +530,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.14.0"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2f7254b99e31cad77da24b08ebf628882739a608578bb1bcdfc1f9c21260d7c0"
+checksum = "e82dad04139b71a90c080c8463fe0dc7902db5192d939bd0950f074d014339e1"
 
 [[package]]
 name = "option_parser"

fuzz/Cargo.toml

@@ -15,7 +15,7 @@ epoll = "4.3.1"
 libc = "0.2.133"
 libfuzzer-sys = "0.4.4"
 micro_http = { git = "https://github.com/firecracker-microvm/micro-http", branch = "main" }
-once_cell = "1.14.0"
+once_cell = "1.15.0"
 qcow = { path = "../qcow" }
 seccompiler = "0.3.0"
 vhdx = { path = "../vhdx" }