Bump openstacksdk to >1

This patch also vendors the openstack.cloud.subnet
module due to a problem with `disable_gateway_ip`
not being set for newly created subnets[1].

[1]: https://review.opendev.org/c/openstack/ansible-collections-openstack/+/940927

Change-Id: Ia021a1d7b82823c2e7498fdd66da3e2d5c6a8a79
(cherry picked from commit 8ccabb61cb8aa6a86c653cc47e43a648e8e07268)
diff --git a/requirements.txt b/requirements.txt
index 9157d5b..038719c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 ansible-core>=2.15.9
 jmespath>=1.0.1
-openstacksdk<0.99.0
+openstacksdk>1
 docker-image-py>=0.1.12
 rjsonnet>=0.5.2
 netaddr>=0.8.0