build: bump indexmap from 1.8.0 to 1.8.1 in /fuzz

Bumps [indexmap](https://github.com/bluss/indexmap) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/bluss/indexmap/releases)
- [Changelog](https://github.com/bluss/indexmap/blob/master/RELEASES.rst)
- [Commits](https://github.com/bluss/indexmap/compare/1.8.0...1.8.1)

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

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

fuzz/Cargo.lock

@@ -325,9 +325,9 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.8.0"
+version = "1.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "282a6247722caba404c065016bbfa522806e51714c34f5dfc3e4a3a46fcb4223"
+checksum = "0f647032dfaa1f8b6dc29bd3edb7bbef4861b8b8007ebb118d6db284fd59f6ee"
 dependencies = [
  "autocfg",
  "hashbrown",