chore: add notice for missing shell-gpt dependency

Added a check for the `sgpt` command and a message prompting users to install
the shell-gpt package if it is not found. This improves user experience by
providing clear instructions for resolving the missing dependency.

scripts/bin/auto_commit

@@ -46,6 +46,7 @@ else
 fi
 
 # Generate the commit message
+hash sgpt || printf "Please install shell-gpt using:\n \npip install shell-gpt\n \nThis will add the 'sgpt' cli tool.\n"
 MSG=$(echo "$DIFF" | sgpt  --model gpt-4o-mini --code "$PROMPT")
 echo "$MSG"