Minimum supported Rust version? #3

Is there an intended MSRV policy for rev_slice?

Currently, the crate itself compiles under Rust 1.28.0 (released 2018-10-02) at the earliest, due to the use of #[repr(transparent)] which was stabilized in that release.

I was looking at adding sort, sort_by, etc, as well as select_nth_unstable, etc, but slice::select_nth_unstable was only stabilized in Rust 1.49.0, so would need to be under a cargo feature or something if this is later than the earliest Rust version you want to support (if you want it added at all).