v6.1.1

Fixed

• Divide by zero with MPCD if rigid body has constituent with zero mass (#2228).
• Ensure that GSD files are always flushed on exit (#2236).
• Code examples in md.nlist, md.angle, md.bond, md.special_pair, md.compute, md.dihedral, md.force, md.integrate, and md.update now execute without errors (#2185).