chainladder v0.8.19

What's Changed

• Docs by @kennethshsu in #464
• Updated star history graph by @kennethshsu in #466
• Roundtable by @kennethshsu in #469
• Roundtable by @kennethshsu in #470
• Roundtable by @kennethshsu in #472
• Update pandas.py by @jbogaardt in #473
• Support for Polars and other dataframes by @johalnes in #482
• fix typo, pytest fixture by @MatthewCaseres in #484
• prepend test_ to test functions by @MatthewCaseres in #485
• fix broken image links by @MatthewCaseres in #488
• fix docstring mismatches by @MatthewCaseres in #492
• make less None in constructor by @MatthewCaseres in #489
• typo fix by @MatthewCaseres in #493
• Update common.py by @jbogaardt in #503
• 497 by @kennethshsu in #501
• 497 by @kennethshsu in #504
• Addressed #420 and #491 by @kennethshsu in #507

Full Changelog: v0.8.18...v0.8.19