Bump tempfile from 3.20.0 to 3.21.0 in /tools/cp-utility (aws-observability#1168)

Author: dependabot[bot]

tools/cp-utility/Cargo.lock

@@ -10,7 +10,7 @@ edition = "2021"
 
 [dev-dependencies]
 # dependencies only used during tests
-tempfile = "3.20.0"
+tempfile = "3.21.0"
 uuid = { version = "1.18.0", features = ["v4", "fast-rng"] }
 
 [profile.release]