Add SWH badge
After Software Heritage & HAL workshop, the repository is archived at SWH, so a badge can be added.
See https://www.softwareheritage.org/2020/01/13/the-swh-badges-are-here/?lang=fr
After Software Heritage & HAL workshop, the repository is archived at SWH, so a badge can be added.
See https://www.softwareheritage.org/2020/01/13/the-swh-badges-are-here/?lang=fr