Update brotli dev-dependency from 6 to 7 (#524)

Author: musicinmybrain

tower-http/Cargo.toml

@@ -41,7 +41,7 @@ uuid = { version = "1.0", features = ["v4"], optional = true }
 
 [dev-dependencies]
 async-trait = "0.1"
-brotli = "6"
+brotli = "7"
 bytes = "1"
 flate2 = "1.0"
 futures-util = "0.3.14"