Please update the version of httplib2

[ashi009]

httplib2 0.11.3 is not capable of picking of system-wide CA bundle changes, which in practice will cause SSL verification failures if the registry is presenting a cert signed by an unsupported CA (including custom ones).

Before #580 is implemented, we should consider updating httplib2 to at least 0.12.0 to load CA bundle in a smarter way (see httplib2/httplib2#2 (comment)).

[alex1545]

Hi @ashi009 and thank you for bringing this up.
You can go ahead and send a PR to update this target and I will be happy to review it.