v0.5.4

Added

• Make Bytes::new a const fn.
• Add From<BytesMut> for Bytes.

Fix

• Fix reversed arguments in PartialOrd for Bytes.
• Fix Bytes::truncate losing original capacity when repr is an unshared Vec.
• Fix Bytes::from(Vec) when allocator gave Vec a pointer with LSB set.
• Fix panic in Bytes::slice_ref if argument is an empty slice.