Remove shaal as maintainer for Umami demo subsystem

xjm → credited shaal → .

Thanks for all the help with Umami over the years, Ofer. Much appreciated.

@smustgrave, thanks for your work on Umami!

Committed to 11.x, 11.2.x, 10.6.x, and 10.5.x. I'll also do the admin tasks, such as updating the core node, the Google group, the maintainer channel and the past maintainer page.

quietone → closed merge request !12736

Think you meant shaal :)

@shaal, Sorry about thanking smustgrave instead of you!

@smustgrave, thank you.