I am the maintainer of this
scMerge package for Bioconductor. The issue that I am having is that Travis seems to be using Bioconductor version 3.8 rather than the newly released 3.9 (https://travis-ci.org/SydneyBioX/scMerge/jobs/529095216). This caused an installation error for a dependent BioC package
M3Drop version >= 1.9.4).
I am unsure if this is a bug or not.