Add SWH badge

README.rst

@@ -23,6 +23,10 @@ Rapid Peptides Generator (RPG) is a software dedicated to predict proteases-indu
     :target: https://rapid-peptide-generator.readthedocs.io/en/latest/?badge=latest
     :alt: Documentation Status
 
+.. image:: https://archive.softwareheritage.org/badge/origin/https://gitlab.pasteur.fr/nmaillet/rpg/
+    :target: https://archive.softwareheritage.org/browse/origin/?origin_url=https://gitlab.pasteur.fr/nmaillet/rpg
+    :alt: Software Heritage Status
+
 :note: RPG is tested with Gitlab Ci for the following Python version: 3.6 to 3.12
 :issues: Please use https://gitlab.pasteur.fr/nmaillet/rpg
 :publication: To cite RPG, please refer to https://doi.org/10.1093/nargab/lqz004