v2.2.0

What's Changed

• Issue 258: change range for started at time and ended at time to datetime by @wdduncan in #264
• Issue 248: deprecate type slot by @wdduncan in #271
• Issue 270: Cannot find get_nmdc_dict() method definition by @wdduncan in #272
• Issue 265: add datetime to validation tool by @wdduncan in #273
• integrate poetry into nmdc-schema repo by @sujaypatil96 in #263

Full Changelog: 2.0.0...v2.2.0