This ticket is to upgrade to cvxopt 1.2.3

• Download page: https://pypi.org/project/cvxopt/#files
• Tarballs:
  • https://files.pythonhosted.org/packages/00/02/13657bcd12d93f53b64a19b68d204f43d5f3247c29287c9eaeefcfa58fb9/cvxopt-1.2.3.tar.gz
  • https://github.com/DrTimothyAldenDavis/SuiteSparse/archive/v5.6.0.tar.gz

[Somehow downloads as SuiteSparse-5.6.0.tar.gz in chromium]
Since cvxopt 1.1.9, SuiteSparse
is no longer included, thus it will have to be packaged separately.

Ticket #19687 was our previous upgrade, to cvxopt 1.1.8 (released 2015-09-22).

CC: @antonio-rojas @embray @kiwifb @timokau @infinity0 @pcpa @saraedum @slel @strogdon @tobihan @sagetrac-tmonteil

Component: packages: standard

Keywords: upgrade, cvxopt

Author: François Bissey

Branch: e23d5c5

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/22380