For now we just need to put the release notes in the final spot. We will
have to fix the date on both 2.90 and 2.91 branches, but such as it is.
Release created with releng/create_release.xsh
Closes: https://git.lix.systems/lix-project/lix/issues/318
Change-Id: I38e79b40e7f632c8a286f2f09865a84dc93eca90