alloc::allocator reexport of alloc::alloc removed; builds failing on latest nightlies

[barzamin]

See https://github.com/rust-lang/rust/commit/26324d0abe1a8df228f8c758b870a38078549ddc. This is currently causing a build failure:

error[E0432]: unresolved import `alloc::allocator`                                                                             
  --> /home/erin/.cargo/registry/src/github.com-1ecc6299db9ec823/linked_list_allocator-0.6.2/src/lib.rs:15:12
   |
15 | use alloc::allocator::{Alloc, AllocErr, Layout};
   |            ^^^^^^^^^ Could not find `allocator` in `alloc`

error[E0432]: unresolved import `alloc::allocator`
 --> /home/erin/.cargo/registry/src/github.com-1ecc6299db9ec823/linked_list_allocator-0.6.2/src/hole.rs:1:12
  |
1 | use alloc::allocator::{AllocErr, Layout};
  |            ^^^^^^^^^ Could not find `allocator` in `alloc`

error: aborting due to 2 previous errors

[phil-opp]

Thanks for reporting! Fixed in b2e5f75, released as version 0.6.3.