async-lock 2.0.0

# Version 2.0.0

- Only re-export `async-mutex` and `async-rwlock`.

# Version 1.1.5

- Replace the implementation with `async-mutex`.

# Version 1.1.4

- Replace `usize::MAX` with `std::usize::MAX`.

# Version 1.1.3

- Update dependencies.

# Version 1.1.2

- Fix a deadlock issue.

# Version 1.1.1

- Fix some typos.

# Version 1.1.0

- Make locking fair.
- Add `LockGuard::source()`.

# Version 1.0.2

- Bump the `event-listener` version.
- Add tests.

# Version 1.0.1

- Update Cargo categories.

# Version 1.0.0

- Initial version