python-heatclient 3.1.0 release

meta:version: 3.1.0
meta:diff-start: -
meta:series: zed
meta:release-type: release
meta:pypi: yes
meta:first: no
meta:release:Author: Elod Illes <elod.illes@est.tech>
meta:release:Commit: Elod Illes <elod.illes@est.tech>
meta:release:Change-Id: I0b75186270411911413ea9595d89949d15f5c81a
meta:release:Code-Review+2: Hervé Beraud <herveberaud.pro@gmail.com>
meta:release:Code-Review+2: Elod Illes <elod.illes@est.tech>
meta:release:Workflow+1: Elod Illes <elod.illes@est.tech>