zshrc: add option to bypass update prompt (#5891)

templates/zshrc.zsh-template

@@ -26,6 +26,9 @@ ZSH_THEME="robbyrussell"
 # Uncomment the following line to disable bi-weekly auto-update checks.
 # DISABLE_AUTO_UPDATE="true"
 
+# Uncomment the following line to automatically update without prompting.
+# DISABLE_UPDATE_PROMPT="true"
+
 # Uncomment the following line to change how often to auto-update (in days).
 # export UPDATE_ZSH_DAYS=13