Update docker.py
Fix error:
Setting up cwltool (3.0.20200324120055+dfsg-2) ... /usr/lib/python3/dist-packages/cwltool/docker.py:423: SyntaxWarning: "is" with a literal. Did you mean "=="? if res_req is not None and ("ramMin" in res_req or "ramMax" is res_req):
(do not merge, just to quick report the patch)
Edited by gleisson joaquim