Update Rust crate insta to v1.21.0 (#5268)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Cargo.lock

@@ -89,7 +89,7 @@ cargo-registry-index = { path = "cargo-registry-index", features = ["testing"] }
 claims = "=0.7.1"
 conduit-test = "=0.10.0"
 hyper-tls = "=0.5.0"
-insta = { version = "=1.20.0", features = ["redactions", "yaml"] }
+insta = { version = "=1.21.0", features = ["redactions", "yaml"] }
 once_cell = "=1.15.0"
 tokio = "=1.21.2"
 tower-service = "=0.3.2"