Release v1.31.9

Changelog

• 920f38b1 [VPN] updated doc in vpnaas_site_connection_v2.md (#2003)

• 4985f201 [NAT] workaround for tags in opentelekomcloud_nat_gateway_v2 for eu-ch region (#2000)

• c43f6044 [CTS]: Complete overhaul of existing resources (#1994)

Full Changelog: https://docs-beta.otc.t-systems.com/releasenotes/terraform-provider-opentelekomcloud#v1-31-9