Uuid 1.2x requires alloc

[Ulf Lilleengen]

What happened?
A clear and concise description of what the bug is.

After the commit c60dd94, the extern crate alloc dependency was added, which requires any no_std environment to use an allocator to use uuid.

Steps to reproduce the behavior:

1. Depend on uuid with default-features false
2. Use uuid in project
3. Observe error message requiring allocator

What were you expecting?

Maybe guarding 'alloc' behind a feature flag?

[Ashley Mannix]

Hm, it shouldn't be necessary for uuid to depend on alloc at all. I think this extern crate should be removed.

[Ashley Mannix]

Thanks for the report @lulf 🙇 And for the benefit of the doubt that this was actually intentional, and not just a very silly oversight. I'll get this released and look into why our embedded target in CI didn't seem to catch it.

[Ulf Lilleengen]

Thanks for fixing it ☺️