v0.4.1: nxontology metadata & python >= 3.8

Commits

• bb4acda fsspec dependency: require http extras
• 7f4ba41 readme: link to nxontology-data
• 4c31d04 add nxontology metadata to new instances
• 14873e1 upgrade python requires >= 3.8

Full Changelog: v0.4.0...v0.4.1