Update handlebars crate to v4.1.3

Author: Turbo87

Cargo.lock

@@ -59,7 +59,7 @@ flate2 = "1.0"
 futures-channel = { version = "0.3.1", default-features = false }
 futures-util = "0.3"
 git2 = "0.13.0"
-handlebars = "3.0.1"
+handlebars = "4.1.3"
 hex = "0.4"
 htmlescape = "0.3.1"
 http = "0.2"