Upgrade when cli is not in use.

[shpengmsft]

az upgrade

az upgrade is blocking my sometimes urgent work for too long.

Upgrading is long running task, but good design could minimize the impact (blocking user form using it in middle of urgent work). It should prepare the upgrade in background task when cli is in use. Then make the quickest changes just like Windows update.

Upgrade on closing (not in use) is good choose, not sure if you can do that just like Visual Studio.

Additional context

[yonzhan]

Thank you for opening this issue, we will look into it.