remove deprecated cargo package settings

pkgs/tools/text/rep-grep/package.nix

@@ -8,6 +8,5 @@ pkgs.rustPlatform.buildRustPackage {
     rev = "2a24f95170aa14b5182b2287125664a62f8688ef";
     sha256 = "sha256-gBxrbGCy6JEHnmgJmcm8sgtEvCAqra8/gPGsfCEfLqg=";
   };
-  useFetchCargoVendor = true;
   cargoHash = "sha256-t4tfQaFq4EV4ZWeU+IestSFiSAIeVQslTZhLbpKVoO4=";
 }