build(deps): bump darling from 0.20.3 to 0.20.4 (#31228)

Bumps [darling](https://github.com/TedDriggs/darling) from 0.20.3 to 0.20.4.
- [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/v0.20.3...v0.20.4)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.lock

@@ -1165,9 +1165,9 @@ dependencies = [
 
 [[package]]
 name = "darling"
-version = "0.20.3"
+version = "0.20.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0209d94da627ab5605dcccf08bb18afa5009cfbef48d8a8b7d7bdbc79be25c5e"
+checksum = "da01daa5f6d41c91358398e8db4dde38e292378da1f28300b59ef4732b879454"
 dependencies = [
  "darling_core",
  "darling_macro",
@@ -1175,9 +1175,9 @@ dependencies = [
 
 [[package]]
 name = "darling_core"
-version = "0.20.3"
+version = "0.20.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "177e3443818124b357d8e76f53be906d60937f0d3a90773a664fa63fa253e621"
+checksum = "f44f6238b948a3c6c3073cdf53bb0c2d5e024ee27e0f35bfe9d556a12395808a"
 dependencies = [
  "fnv",
  "ident_case",
@@ -1188,9 +1188,9 @@ dependencies = [
 
 [[package]]
 name = "darling_macro"
-version = "0.20.3"
+version = "0.20.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "836a9bbc7ad63342d6d6e7b815ccab164bc77a2d95d84bc3117a8c0d5c98e2d5"
+checksum = "0d2d88bd93979b1feb760a6b5c531ac5ba06bd63e74894c377af02faee07b9cd"
 dependencies = [
  "darling_core",
  "quote",