Upgrade mio-aio to 0.8.0

[Darksonn]

This upgrades a test-only dependency for testing FreeBSD to 0.8.0. This allows us to remove an ignored CVE from our .cargo/audit.toml file. (See #4255 (comment).)

cc @asomers

[Darksonn]

This is more complicated than I thought it would be ...

[asomers]

Thanks for looking at this. I'm on vacation now, but I can help next week. Right now, i can't even see the ci failures, not on github's phone ui.

[Darksonn]

That would be very helpful!

The compilation failure is as follows:

error[E0432]: unresolved imports `mio_aio::AioCb`, `mio_aio::LioCb`
 --> tokio/tests/io_poll_aio.rs:4:15
  |
4 | use mio_aio::{AioCb, AioFsyncMode, LioCb};
  |               ^^^^^                ^^^^^ no `LioCb` in the root
  |               |
  |               no `AioCb` in the root

error[E0433]: failed to resolve: could not find `LioCbBuilder` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:313:36
    |
313 |         let mut builder = mio_aio::LioCbBuilder::with_capacity(1);
    |                                    ^^^^^^^^^^^^ could not find `LioCbBuilder` in `mio_aio`

error[E0433]: failed to resolve: could not find `LioOpcode` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:319:22
    |
319 |             mio_aio::LioOpcode::LIO_WRITE,
    |                      ^^^^^^^^^ could not find `LioOpcode` in `mio_aio`

error[E0433]: failed to resolve: could not find `LioCbBuilder` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:339:37
    |
339 |         let mut builder0 = mio_aio::LioCbBuilder::with_capacity(1);
    |                                     ^^^^^^^^^^^^ could not find `LioCbBuilder` in `mio_aio`

error[E0433]: failed to resolve: could not find `LioOpcode` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:345:22
    |
345 |             mio_aio::LioOpcode::LIO_WRITE,
    |                      ^^^^^^^^^ could not find `LioOpcode` in `mio_aio`

error[E0433]: failed to resolve: could not find `LioCbBuilder` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:357:37
    |
357 |         let mut builder1 = mio_aio::LioCbBuilder::with_capacity(1);
    |                                     ^^^^^^^^^^^^ could not find `LioCbBuilder` in `mio_aio`

error[E0433]: failed to resolve: could not find `LioOpcode` in `mio_aio`
   --> tokio/tests/io_poll_aio.rs:363:22
    |
363 |             mio_aio::LioOpcode::LIO_WRITE,
    |                      ^^^^^^^^^ could not find `LioOpcode` in `mio_aio`

Some errors have detailed explanations: E0432, E0433.
For more information about an error, try `rustc --explain E0432`.
error: could not compile `tokio` (test "io_poll_aio") due to 7 previous errors
warning: build failed, waiting for other jobs to finish...

Exit status: 101