build: Bump darling from 0.20.5 to 0.20.6 in /fuzz

Bumps [darling](https://github.com/TedDriggs/darling) from 0.20.5 to 0.20.6.
- [Release notes](https://github.com/TedDriggs/darling/releases)
- [Changelog](https://github.com/TedDriggs/darling/blob/master/CHANGELOG.md)
- [Commits](https://github.com/TedDriggs/darling/compare/v0.20.5...v0.20.6)

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

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

fuzz/Cargo.lock

@@ -211,7 +211,7 @@ checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
 
 [[package]]
 name = "cloud-hypervisor"
-version = "37.0.0"
+version = "38.0.0"
 dependencies = [
  "anyhow",
  "api_client",
@@ -281,9 +281,9 @@ checksum = "2707e3afba5e19b75d582d88bc79237418f2a2a2d673d01cf9b03633b46e98f3"
 
 [[package]]
 name = "darling"
-version = "0.20.5"
+version = "0.20.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc5d6b04b3fd0ba9926f945895de7d806260a2d7431ba82e7edaecb043c4c6b8"
+checksum = "c376d08ea6aa96aafe61237c7200d1241cb177b7d3a542d791f2d118e9cbb955"
 dependencies = [
  "darling_core",
  "darling_macro",
@@ -291,9 +291,9 @@ dependencies = [
 
 [[package]]
 name = "darling_core"
-version = "0.20.5"
+version = "0.20.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "04e48a959bcd5c761246f5d090ebc2fbf7b9cd527a492b07a67510c108f1e7e3"
+checksum = "33043dcd19068b8192064c704b3f83eb464f91f1ff527b44a4e2b08d9cdb8855"
 dependencies = [
  "fnv",
  "ident_case",
@@ -305,9 +305,9 @@ dependencies = [
 
 [[package]]
 name = "darling_macro"
-version = "0.20.5"
+version = "0.20.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d1545d67a2149e1d93b7e5c7752dce5a7426eb5d1357ddcfd89336b94444f77"
+checksum = "c5a91391accf613803c2a9bf9abccdbaa07c54b4244a5b64883f9c3c137c86be"
 dependencies = [
  "darling_core",
  "quote",