x509-cert: fixup CI flakiness

rsa 0.9.1 provides a fix for invalid signatures sometimes generated

Author: baloo

Cargo.lock

@@ -27,7 +27,7 @@ signature = { version = "2.1.0", features = ["rand_core"], optional = true }
 [dev-dependencies]
 hex-literal = "0.4"
 rand = "0.8.5"
-rsa = { version = "0.9.0", features = ["sha2"] }
+rsa = { version = "0.9.1", features = ["sha2"] }
 ecdsa = { version = "0.16.4", features = ["digest", "pem"] }
 p256 = "0.13.0"
 rstest = "0.17"