Pin to lscsoft-glue <4.0.0

The glue.ligolw subpackage will be removed as of lscsoft-glue version 4.0.0, so this project needs to pin to versions older than that, at least until Migrate from glue.ligolw to ligo.lw for LIGO_LW... (#23 - closed) is completed.

See Remove glue.ligolw (lscsoft/glue#33 - closed) for details.