* Update CHANGELOG with release notes URL.
* Update README with new release number & name.
* Update metadata.json with new tag & dependencies.
* Add release note prelude for Mitaka.
* Update Reno release note to drop prelude.
* Improve release note landing page.
Change-Id: Ic9c0531e635bbcb90c4c18a140a8e9e352d8e86b