Bump async-task

[Zeophlite]

Bumps async-task to 4.7.0 , note this is what Cargo.lock has as well. Building as a dependency gives the following:

   Compiling async-channel v1.8.0
   Compiling futures-lite v1.12.0
error[E0432]: unresolved import `async_task::Builder`
  --> /Users/daniel/.cargo/registry/src/index.crates.io-6f17d22bba15001f/async-executor-1.8.0/src/lib.rs:46:18
   |
46 | use async_task::{Builder, Runnable};
   |                  ^^^^^^^ no `Builder` in the root
   |
   = help: consider importing this struct instead:
           std::thread::Builder

For more information about this error, try `rustc --explain E0432`.
error: could not compile `async-executor` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...

With this change, builds correctly

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[BD103]

I did a little testing. cargo c -p bevy_tasks fails with async-task = "=4.3.0", but succeeds with "=4.4.0". This PR technically bumps the version past where it needs to be to fix the bug, but I don't think that's a problem.