`speaklater` requirements

[MementoRC]

speaklater3 does not seem to be supported (no github page). speaklater was the origin for it and the updates seemed to only add Python2 support. Would it be possible to use a selector for users not interested in python2 support? This is related to our efforts to bring pgadmin4 to the conda environment. Conda environment does not support python <=3.8 and thus it feels moot to add speaklater3