fix(serde): update to latest serde/rust

src/mako/Cargo.toml.mako

@@ -29,8 +29,8 @@ name = "${util.program_name()}"
 hyper = ">= 0.6.8"
 ## Must match the one hyper uses, otherwise there are duplicate similarly named `Mime` structs
 mime = "0.1.0"
-serde = ">= 0.5.0"
-serde_json = "*"
+serde = ">= 0.6.0"
+serde_json = ">= 0.6.0"
 yup-oauth2 = "*"
 % for dep in cargo.get('dependencies', list()):
 ${dep}