Display a warning on dev docs
This MR updates the docs configuration to display a warning on development docs versions, with links to the latest stable version.
Maintenance will be performed on git.ligo.org, containers.ligo.org, and docs.ligo.org on Tuesday 2 July 2024 starting at approximately 9:30am PDT. It is expected to take around two hours and there will be several periods of downtime throughout the maintenance. Please address any comments, concerns, or questions to the helpdesk.
This MR updates the docs configuration to display a warning on development docs versions, with links to the latest stable version.