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

[Debian testing autoremoval watch]

ruby-active-model-serializers 0.10.10-1 is marked for autoremoval from testing on 2020-03-28

It is affected by these RC bugs:
952031: ruby-active-model-serializers: FTBFS: ERROR: Test "ruby2.7" failed.

It (build-)depends on packages with these RC bugs:
949493: ruby-libxml: FTBFS with libxml2 2.9.10
952025: ruby-grape: FTBFS: ERROR: Test "ruby2.7" failed:      Failure/Error: spec = parsers(**options)[api_format]