fix(cargo): choose serde-version which works

Everything newer than the ones we see here will cause
the error described in #148.

src/mako/Cargo.toml.mako

@@ -26,19 +26,19 @@ name = "${util.program_name()}"
 % endif
 
 [dependencies]
-hyper = "0.7"
+hyper = "0.8"
 ## Must match the one hyper uses, otherwise there are duplicate similarly named `Mime` structs
-mime = "0.1.0"
-serde = ">= 0.7.0"
-serde_json = ">= 0.7.0"
-yup-oauth2 = ">= 0.5.4"
+mime = "0.2.0"
+serde = "0.6.0"
+serde_json = "0.6.0"
+yup-oauth2 = ">= 0.5.5"
 % for dep in cargo.get('dependencies', list()):
 ${dep}
 % endfor
 
 [build-dependencies]
-syntex = { version = ">= 0.23" }
-serde_codegen = { version = ">= 0.6" }
+syntex = { version = "= 0.28" }
+serde_codegen = { version = "= 0.6.13" }
 
 % if make.depends_on_suffix is not None: