AAVSO#502: updated release date in change log

AAVSO#502: updated release date in change log

updated citation file and revision accessor

updated date in citation file

Tag for the 2.22.0 release.

updated build number

2.21.3 release

Merge pull request AAVSO#73 from AAVSO/issue-68-lightkurve

Issue 68 lightkurve

Merge pull request AAVSO#69 from AAVSO/issue-67-HJD-neg-dec

AAVSO#67: fixed dec min/max in dialog field; also fixed RA min/max

Merge pull request AAVSO#69 from AAVSO/issue-67-HJD-neg-dec

AAVSO#67: fixed dec min/max in dialog field; also fixed RA min/max