[docker] switch to ldap3>=2

Now logilab/cubicweb:dev use a cubicweb compatible with ldap3>=2

docker/requirements.txt

 # extra requirements to be installed in docker
 pyramid-redis-sessions
 cubicweb-trustedauth
-https://github.com/cannatag/ldap3/archive/0.9.5.1.tar.gz
+ldap3>=2,<3