upgrade Ubuntu from wsl to wsl2

PS C:\Users\alex> wsl -l -v NAME STATE VERSION
* Ubuntu Running 1
docker-desktop-data Running 2
docker-desktop Running 2
Ubuntu-20.04 Stopped 2
PS C:\Users\alex> wsl --set-version Ubuntu 2Conversion in progress, this may take a few minutes...
For information on key differences with WSL 2 please visit https://aka.ms/wsl2
Conversion complete.
PS C:\Users\alex> wsl -l -v NAME STATE VERSION
* Ubuntu Stopped 2
docker-desktop-data Running 2
docker-desktop Running 2
Ubuntu-20.04 Stopped 2
PS C:\Users\alex>