Print usage info when only -v is given

ghcup

@@ -741,7 +741,11 @@ while [ $# -gt 0 ] ; do
     case $1 in
     -v|--verbose)
         VERBOSE=true
-        shift 1;;
+        shift 1
+        if [ $# -lt 1 ] ; then
+            usage
+        fi
+        ;;
     -V|--version)
         printf "%s" "${VERSION}"
         exit 0;;