Tracking issue for building RLS for aarch64-pc-windows-msvc

[arlosi]

Building RLS for aarch64-pc-windows-msvc currently fails because of a transitive dependency on winapi 0.2, which does not support aarch64.

The dependency chain is rls -> tokio 0.2 -> mio 0.6 -> winapi 0.2.

mio 0.7 avoids the dependency on winapi 0.2, however it has not yet been integrated into tokio.
tokio-rs/tokio#1190

mio-named-pipes may also need to be updated:
bbqsrc/mio-named-pipes#7