[Isbg] Changing the Read the docs source to the main ISGB repository

Hi Carles! I'm happy to tell you we merged your PR and the `v.2.0` branch has now been merged with the master branch. Do you think you could change the Read the docs source to the main ISGB repository? That was we can keep the online doc up to date. Thanks! -- ,''`. : :' : Louis-Philippe Véronneau `. `'` pollo@debian.org / veronneau.org `-