Submit the new version of WebStorm to Flathub

Hi,

WebStorm on Flathub is not officially maintained by JetBrains, but rather by third-party contributors.
I've created an issue to request an update to the latest version here:
https://github.com/flathub/com.jetbrains.WebStorm/issues/127

As a workaround, you can try the tar.gz version here: https://www.jetbrains.com/webstorm/download/other.html