serenity: Transfer ownership to current project admin (#12612)

I am no longer involved with this project, so let's make @gmta the
primary contact since he's the chief admin of SerenityOS now. :)

projects/serenity/project.yaml

@@ -1,6 +1,6 @@
 homepage: "https://github.com/SerenityOS/serenity"
 language: c++
-primary_contact: "[email protected]"
+primary_contact: "[email protected]"
 auto_ccs:
   - "[email protected]"
   - "[email protected]"
@@ -12,7 +12,6 @@ auto_ccs:
   - "[email protected]"
   - "[email protected]"
   - "[email protected]"
-  - "~awesomekling/[email protected]"
 
 # Bug reports are public by default:
 view_restrictions: none