Bump to alacritty 0.5.0 (which is happening by fetching YANNPP (Yet
Another Nixpkgs Pin) because overriding versions of rust packages is not
very well supported) and update the relevant home-manager version and
pin to get it installed and configured with vi-mode.
Change-Id: I4fd96bd0c0611ce76500c33bf0b2c680ee7f44c3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1583
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>