release 0.8.5

Patch-level release with no functional changes (only minor bug fixes and house-keeping, see below).

This is the last release to support very old Python versions (2.7, <3.7) — see #259 .

What's Changed

• use pandas.testing.assert_frame_equal by @orbeckst in #250
• modernized CI workflow by @orbeckst in #254
• Blacken by @orbeckst in #247
• test GROMACS 2023.1 (and use Py 3.11 for the all version test) by @orbeckst in #255

Full Changelog: release-0.8.4...release-0.8.5