[fish] Add GIT_CU_DIR to fish config

fish/.config/fish/config.fish

@@ -3,6 +3,7 @@ set -gx PATH ~/.cargo/bin $PATH
 set -gx PATH ~/.bin $PATH
 set -gx PATH ~/.screenlayout $PATH
 set -gx PATH ~/.emacs.d/bin $PATH
+set -gx GIT_CU_DIR ~/src
 #set -gx PATH ~/.fzf/bin $PATH
 set -gx PATH ~/.local/bin $PATH
 fzf_key_bindings