[DRE-maint] ruby-active-model-serializers is marked for autoremoval from testing

[Debian testing autoremoval watch]

ruby-active-model-serializers 0.10.8-1 is marked for autoremoval from testing on 2020-03-14

It (build-)depends on packages with these RC bugs:
950228: ruby-kaminari: autopkgtest needs update for new version of gem2deb