fix(avit): replace deprecated GREP_COLOR (#11168)

themes/avit.zsh-theme

@@ -82,4 +82,4 @@ ZSH_THEME_GIT_TIME_SINCE_COMMIT_NEUTRAL="%{$fg[white]%}"
 # LS colors, made with https://geoff.greer.fm/lscolors/
 export LSCOLORS="exfxcxdxbxegedabagacad"
 export LS_COLORS='di=34;40:ln=35;40:so=32;40:pi=33;40:ex=31;40:bd=34;46:cd=34;43:su=0;41:sg=0;46:tw=0;42:ow=0;43:'
-export GREP_COLOR='1;33'
+export GREP_COLORS='mt=1;33'