This has the following upsides:
- fixes pkgcheck scan's `TooManyCrates` warning.
- becomes more easy to maintain since all it takes is a new vendor file
and bumping the ebuild.
- saves time for users. Portage doesn't try to download 500+ crates from
gentoo mirrors first then trying the crates.io links, instead, it just
downloads one singular vendor file
Signed-off-by: ingenarel <ingenarelitems@gmail.com>