Document publicationDate properties invalid in Safari

[udyux]

In Safari (tested on 10.0.3), firstPublicationDate and lastPublicationDate properties are returned as Invalid Date. See this StackOverflow question for a possible lead on fixing the issue.

I hoped a workaround could be parsing the string timestamp (first_publication_date) myself but it doesn't seem to be exposed on the response object.

Both properties work correctly in Chrome and Firefox.

[srenault]

We'll look at it ASAP. Thanks for reporting this.

[arnaudlewis]

Fixed in the latest release with this PR #151