Fix project URLs in README
The project has been moved, update the URLs in README.md accordingly.
You don't pay for Framagit, because it is funded by donations to Framasoft. Our not-for-profit needs any support you can afford: support.framasoft.org.
Framagit est gratuit car il est financé par les dons à Framasoft. Notre association a besoin de votre soutien sur soutenir.framasoft.org.
The project has been moved, update the URLs in README.md accordingly.