Changelog for release 2.0.11

[jrfnl]

• Includes updating the version number constant.

[jrfnl]

Release checklist

• Check if any dependencies need updating. - N/A
• Update the version constant in src/Requests.php - this PR
• Add changelog for the release - this PR
• Merge this PR.
• Make sure all CI builds are green.
• Tag the release against stable and push the tag.
• Review the automatically created PR with the GH Pages docs update.
• Create a release from the tag (careful, GH defaults to develop!) & copy & paste the changelog to it.
  Make sure to copy the links to the issues and the links to the GH usernames from the bottom of the changelog!
• Merge the GH Pages PR.
  Note: it is important to do this after the release as otherwise the information about the latest release
  in the site will not be updated correctly from the GitHub API.
• Verify that the website regenerated correctly and is in working order.
• Close the milestone.
• Open a new milestone for the next release.
• If any open PRs/issues which were milestoned for the release did not make it into the release, update their milestone.
• Tweet about the release.
• Post about it in the WP #core Slack channel.
• Open a Trac ticket for WordPress Core to update their copy.
• Submit for "Month in WordPress": https://make.wordpress.org/community/month-in-wordpress-submissions/