docs(README): add mise alternative method installation

Signed-off-by: jylenhof <[email protected]>

Author: jylenhof

README.md

@@ -163,6 +163,12 @@ scoop install gitui
 choco install gitui
 ```
 
+##### [Mise](https://github.com/jdx/mise)
+
+```shell
+mise use -g gitui@latest
+```
+
 ##### [Nix](https://search.nixos.org/packages?channel=unstable&show=gitui&from=0&size=50&sort=relevance&query=gitui) (Nix/NixOS)
 
 Nixpkg