Update rand dependency because of RUSTSEC-2021-0023

Author: jhorstmann

Cargo.toml

@@ -44,7 +44,7 @@ url = { version = "2.1.1", features = ["serde"] }
 serde_json = "1.0.51"
 serde = { version = "1.0.106", features = ["derive"] }
 serde_urlencoded = "0.7.0"
-rand = "0.7.3"
+rand = "0.8.5"
 serde_qs = "0.8.3"
 base64 = "0.13.0"