update constraint for neutron-lib to new release 3.18.1

meta: version: 3.18.1
meta: team: neutron
meta: diff-start: -
meta: series: epoxy
meta: branch: master
meta: release-type: release
meta: pypi: yes
meta: first: no
meta: release:Author: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
meta: release:Commit: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
meta: release:Change-Id: I6be468fedd0c6cdce836b44cdbefbb91dc382ee8
meta: release:Code-Review+1: Brian Haley <haleyb.dev@gmail.com>
meta: release:Code-Review+1: yatin <ykarel@redhat.com>
meta: release:Workflow+1: Thierry Carrez <thierry@openstack.org>
meta: release:Code-Review+2: Thierry Carrez <thierry@openstack.org>
meta: release:Code-Review+2: Elod Illes <elod.illes@est.tech>
Change-Id: I0b413b9ad94a75fa7c56e73f2fc1cd8fd060c6b3

Author: OpenStack Proposal Bot

upper-constraints.txt

@@ -59,7 +59,7 @@ pycadf===4.0.1
 grpcio===1.70.0
 sniffio===1.3.1
 fixtures===4.2.2
-neutron-lib===3.18.0
+neutron-lib===3.18.1
 XStatic-FileSaver===1.3.2.0
 jaraco.functools===4.1.0
 jaraco.text===4.0.0