bump baseVersion to 2.13.1
bump baseVersion to 2.13.1

little missing piece of #8132

scala/scala,scala/scala,lrytz/scala,martijnhoekstra/scala,lrytz/scala,lrytz/scala,martijnhoekstra/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,scala/scala,lrytz/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,scala/scala,martijnhoekstra/scala