Update bleach to 3.3.0
Update bleach to 3.3.0

The security issue does not affect our usage, but let's avoid warnings
that may scare people...

closes #4770

pferreir/indico,pferreir/indico,pferreir/indico,ThiefMaster/indico,ThiefMaster/indico,indico/indico,ThiefMaster/indico,indico/indico,pferreir/indico,ThiefMaster/indico,indico/indico,DirkHoffmann/indico,DirkHoffmann/indico,DirkHoffmann/indico,DirkHoffmann/indico,indico/indico