Upgrade Rust version, repair CI status

[secretfader]

The dependency that seems to be preventing a successful CI run is tide-cors (see #38). We don't have a need to build that middleware while testing http-service-lambda, so I removed it (along with other extra features).

Hopefully this corrects my mistake of breaking CI on master.
cc: @rustasync/maintainers

[secretfader]

After further research, I realized this error was the result of changes in rustasync/tide#288. I've updated the nightly version to match, and re-titled the PR to more clearly reflect the nature of my suggested changes. (We still don't need to compile all default middleware with Tide, so those changes remain.)