chore(Cargo.toml): add feature "backtrace" as a default

Author: hasezoey

Cargo.toml

@@ -11,9 +11,10 @@ authors = ["Haris <[email protected]>"]
 edition = "2021"
 
 [features]
-default = ["tsync"]
+default = ["tsync", "backtrace"]
 tsync = []
 async = []
+backtrace = []
 
 [dependencies]
 structopt = "0.3"