fix(prost): Remove unconditional enable of tonic-build transport feature (#2357)

Author: tottoto

tonic-prost-build/Cargo.toml

@@ -17,7 +17,7 @@ transport = ["tonic-build/transport"]
 cleanup-markdown = ["prost-build/cleanup-markdown"]
 
 [dependencies]
-tonic-build = { version = "0.14.0", path = "../tonic-build", default-features = false, features = ["transport"] }
+tonic-build = { version = "0.14.0", path = "../tonic-build", default-features = false }
 prost-build = { version = "0.14" }
 prost-types = { version = "0.14" }
 prettyplease = { version = "0.2" }