v0.5.1: Merge pull request #22 from DaveStrickland/issue-021

What's Changed

• Issue 015 Sphinx documentation generation does not work by @DaveStrickland in #18
• Issue 017 ApAddMetadata fails on iTelescope Premium Image sets by @DaveStrickland in #19
• Resolve Issue 021 - Adapt to astropy 6 API changes by @DaveStrickland in #22

Full Changelog: v0.4.2...v0.5.1