wrong directions for setup in `README.md`

[Lalit Kumar]

I am not sure, if this is incorrect or not. But please have a look.

I think, the code for the vimscript should use require('smartyank') instead of require('fzf-lua').

Please check.

[ibhagwan]

Ty @lalitmee, I copied this part of the README from my other plug-in and missed that :)