build: Bump signal-hook from 0.3.14 to 0.3.15 in /fuzz

Bumps [signal-hook](https://github.com/vorner/signal-hook) from 0.3.14 to 0.3.15.
- [Release notes](https://github.com/vorner/signal-hook/releases)
- [Changelog](https://github.com/vorner/signal-hook/blob/master/CHANGELOG.md)
- [Commits](https://github.com/vorner/signal-hook/compare/v0.3.14...v0.3.15)

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

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

fuzz/Cargo.lock

@@ -634,9 +634,9 @@ version = "0.1.0"
 
 [[package]]
 name = "signal-hook"
-version = "0.3.14"
+version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a253b5e89e2698464fc26b545c9edceb338e18a89effeeecfea192c3025be29d"
+checksum = "732768f1176d21d09e076c23a93123d40bba92d50c4058da34d45c8de8e682b9"
 dependencies = [
  "libc",
  "signal-hook-registry",
@@ -788,6 +788,7 @@ dependencies = [
 name = "vfio_user"
 version = "0.1.0"
 dependencies = [
+ "bitflags",
  "libc",
  "log",
  "serde",