All Constellation libraries have been upgraded to the Sitecore 9.1.1 Package References. There are no functional changes in this update other than the compatibility upgrade.
All supported Constellation NuGet packages now contain up-to-date Project references to this website along with links to the source repository on GitHub. The MIT license is now explicitly referenced in the package, as recommended by NuGet.org. Constellation also now has an icon!
During the upgrade process, I found that Sitecore 9.1.1 was very backwards compatible with 9.1.0 (as you’d expect). Given the large number of bug fixes in 9.1.1 I would recommend upgrading any 9.x work-in-progress to 9.1.1. After upgrading Sitecore, upgrade Constellation via the NuGet package manager in Visual Studio.