Date-related spec documentation link in readme.md is dead link

[stonefrango]

Note that the original pubDate field is available under published attribute for the given feed entry. Other date-type values that can be available are updated, created and expired. Please refer to the documentation of the original feedparser library.

The link https://feedparser.readthedocs.io/en/latest/date-parsing.html is a dead link, returns a 404.

[stonefrango]

Link should now be: https://feedparser.readthedocs.io/en/latest/date-parsing/