Remove Fig

Fig is no more (see https://app.fig.io/plugins/z.lua)

README.md

@@ -58,15 +58,6 @@ z -b foo bar # replace foo with bar in cwd and cd there
 
 ## Install
 
-- Fig (works with all shells)
-
-  [Fig](https://fig.io) adds apps, shortcuts, and autocomplete to your existing terminal.
-
-
-    Install `z.lua` in just one click.
-
-  <a href="https://fig.io/plugins/other/z.lua" target="_blank"><img src="https://fig.io/badges/install-with-fig.svg" /></a>
-
 - Bash:
 
   put something like this in your `.bashrc`: