Update CONTRIBUTING file
Update CONTRIBUTING file

FabienM/wallabag,egilli/wallabag,wallabag/wallabag,shtrom/wallabag,X-dark/wallabag,egilli/wallabag,shtrom/wallabag,pmichelazzo/wallabag,FabienM/wallabag,wallabag/wallabag,pmichelazzo/wallabag,X-dark/wallabag,shtrom/wallabag,shtrom/wallabag,egilli/wallabag,pmichelazzo/wallabag,pmichelazzo/wallabag,X-dark/wallabag,X-dark/wallabag,shtrom/wallabag,wallabag/wallabag,pmichelazzo/wallabag,FabienM/wallabag,egilli/wallabag,X-dark/wallabag,egilli/wallabag,FabienM/wallabag