Update toml_edit requirement from 0.21 to 0.22

Updates the requirements on [toml_edit](https://github.com/toml-rs/toml) to permit the latest version.
- [Commits](toml-rs/toml@v0.21.0...v0.22.4)

---
updated-dependencies:
- dependency-name: toml_edit
  dependency-type: direct:production
...

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

sys-testing/Cargo.toml

@@ -15,7 +15,7 @@ aws-lc-fips-sys = { path = "../aws-lc-fips-sys", optional = true }
 
 [build-dependencies]
 cc = "1"
-toml_edit = "0.21"
+toml_edit = "0.22"
 
 [package.metadata.cargo-udeps.ignore]
 normal = [ "aws-lc-sys", "aws-lc-fips-sys" ] # the sys crate is only used through a C library build