add auto completion on ng update (#7244)

add new option update and add all the options for ng update

plugins/ng/ng.plugin.zsh

 
-ng_opts='addon asset-sizes b build completion d destroy doc e2e g generate get github-pages:deploy gh-pages:deploy h help i init install lint make-this-awesome new s serve server set t test v version -h --help'
+ng_opts='addon asset-sizes b build completion d destroy doc e2e g generate get github-pages:deploy gh-pages:deploy h help i init install lint make-this-awesome new s serve server set t test update v version -h --help'
 
 _ng_completion () {
   local words cword opts
@@ -56,6 +56,10 @@ _ng_completion () {
       opts='--browsers --colors --config-file --environment --filter --host --launch --log-level --module --path --port --query --reporter --server --silent --test-page --test-port --watch -H -c -cf -e -f -m -r -s -tp -w'
       ;;
       
+    update )
+      opts='--all --dryRun --force --from --migrate-only --next --registry --to -d'
+      ;;
+
     v | version )
       opts='--verbose'
       ;;