Release badges
This merge request adds release badges to the README and various documentation pages.
With this, every time we publish the docs by running a pipeline on the master
branch, the static svg
badges will be regenerated based on the existing tags in the repository.
The README and documentation refer to the badges directly at buildstream.gitlab.io
, so any static copy of the documentation will show the updated badge by retrieving the latest one.
Edited by Tristan Van Berkom