fix #80

[huang12zheng]

No description provided.

[chipsenkbeil]

@huang12zheng I think the new version of async-graphql needs a newer version of Rust to support cargo for the 2021 edition. The minimum version of 1.49.0 is quite old, so I'm fine with us bumping up the version to something much newer.

Separately, for the nightly tests, the compilation error checks are failing, but skimming through them I think you can just run the tests with TRYBUILD=overwrite since it's just the wording that changed a little bit.

Other than those two adjustments, there was something minor with clippy that needs to be fixed up.

[chipsenkbeil]

Sorry, when I said run tests with TRYBUILD=overwrite, I meant run them manually with that environment variable set. It will overwrite some files that we can check into your PR.

We don't want to always set it as that will cause our macro ui tests to always overwrite, which can cause real failures to get hidden.

Check out trybuild for more info on those tests: https://github.com/dtolnay/trybuild