Merge pull request 155 from jfirebaugh/patch-1

Author: dtolnay

Cargo.toml

@@ -15,7 +15,7 @@ default = ["std"]
 std = []
 
 [dependencies]
-backtrace = { version = "0.3", optional = true }
+backtrace = { version = "0.3.51", optional = true }
 
 [dev-dependencies]
 futures = { version = "0.3", default-features = false }