update constraint for python-freezerclient to new release 6.0.0

meta: version: 6.0.0
meta: team: freezer
meta: diff-start: -
meta: series: epoxy
meta: branch: master
meta: release-type: release
meta: pypi: yes
meta: first: yes
meta: release:Author: Dmitriy Rabotyagov <dmitriy.rabotyagov@cleura.com>
meta: release:Commit: Thierry Carrez <thierry@openstack.org>
meta: release:Change-Id: I522861e08bd513e7517874d98d9f2868c9fb0e7a
meta: release:Code-Review+2: Thierry Carrez <thierry@openstack.org>
meta: release:Code-Review+2: Elod Illes <elod.illes@est.tech>
meta: release:Workflow+1: Elod Illes <elod.illes@est.tech>
Change-Id: I9ba50614da8fd7ac267dd4b478e3c22be8839f10

Author: OpenStack Proposal Bot

upper-constraints.txt

@@ -84,7 +84,7 @@ pyserial===3.5
 moto===5.0.27
 infi.dtypes.wwn===0.1.1
 rpm-vercmp===0.1.2
-python-freezerclient===5.2.0
+python-freezerclient===6.0.0
 python-vitrageclient===5.2.0
 py-pure-client===1.61.0
 krest===1.3.6