Keep ScalarValue but mark it as deprecated

Author: LegNeato

juniper_codegen/src/lib.rs

@@ -68,6 +68,12 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
     gen.into()
 }
 
+#[deprecated(note = "ScalarValue has been renamed to GraphQLScalarValue")]
+#[proc_macro_derive(ScalarValue)]
+pub fn derive_scalar_value_deprecated(input: TokenStream) -> TokenStream {
+    derive_scalar_value(input)
+}
+
 #[proc_macro_derive(GraphQLScalarValueInternal)]
 #[doc(hidden)]
 pub fn derive_scalar_value_internal(input: TokenStream) -> TokenStream {