Remove proeung as maintainer for Olivero subsystem

Thank you @proeung for what you've done to help make olivero what it is today

xjm → credited proeung → .

Putra was instrumental in early Olivero work. In fact, it was her idea to get it off the ground and *really* do it. I remember the airport discussion with her (post DrupalCon Seattle) when we discussed it. It seems so long ago yet so close.

Here we are pre-FLDC 2020 sprinting. I remember I had a really bad head cold, but I was still stoked to keep working on it

Thanks so much Putra! I'm sure we'll run into each other again soon!