update constraint for openstack-release-test to new release 8.1.0

meta: version: 8.1.0
meta: team: Release Management
meta: diff-start: -
meta: series: flamingo
meta: branch: master
meta: release-type: release
meta: pypi: no
meta: first: yes
meta: release:Author: Előd Illés <elod.illes@est.tech>
meta: release:Commit: Előd Illés <elod.illes@est.tech>
meta: release:Change-Id: I3a50541f791329cd7841c3b8d4c558f165d97fb6
meta: release:Workflow+1: Elod Illes <elod.illes@est.tech>
meta: release:Code-Review+2: Elod Illes <elod.illes@est.tech>
Change-Id: I85e375a14746e9137012f985602f8cd4b8050ffb

Author: OpenStack Proposal Bot

upper-constraints.txt

@@ -193,7 +193,7 @@ httpcore===1.0.7
 URLObject===2.4.3
 psycopg2-binary===2.9.10
 glance_store===4.9.1
-openstack-release-test===8.0.0
+openstack-release-test===8.1.0
 pycryptodomex===3.21.0
 requests-mock===1.12.1
 os-apply-config===14.0.0