v3.18

Fixed

• Fixed incorrect handling of HTTP client libraries when httpx is not installed (should graciously fallback to
  requests). Reported by drws <https://github.com/drws>__ as an add-on to issuse #66 <https://github.com/mborsetti/webchanges/issues/66>__.

Added

• Job directive enabled to allow disabling of a job without removing or commenting it in the jobs file (contributed
  by James Hewitt <https://github.com/Jamstah>__ upstream <https://github.com/thp/urlwatch/pull/785>__).
• webhook reporter has a new rich_text config option for preformatted rich text for Slack (contributed
  by K̶e̶v̶i̶n̶ <https://github.com/vimagick>__ upstream <https://github.com/thp/urlwatch/pull/780>__).

Changed

• Command line argument --errors now uses conditional requests to improve speed. Do not use to test newly modified
  jobs since websites reporting no changes from the last snapshot stored by webchanges are skipped; use
  --test instead.
• If the simplejson library is installed, it will be used instead of the built-in json module (see
  https://stackoverflow.com/questions/712791).