Microsoft has backported Windows Subsystem for Linux 2 to Windows 10 version 1903 and 1909. WSL2 includes a real Linux kernel, improved performance, and better application compatibility. Docker Desktop has added support for WSL 2 as their engine, which now allows it to be used in Windows 10 versions 1903-2004. If you already have WSL installed, you should upgrade your existing WSL distributions to WSL1 to get the feature in WSL-2 in your Windows 10..installation..systems.
Source: https://www.bleepingcomputer.com/news/microsoft/wsl2-now-rolling-out-to-devices-running-windows-10-1903-and-1909/