Add py39 testing to nodepool

Typically we would drop py38 testing at this point, but since Zuul is
still running on py38 we keep py38 here until both can be running py39.

Change-Id: Ic89f1379e50c2b6d73f0fa4687635cf20ae3dec1

.zuul.yaml

@@ -271,6 +271,14 @@
     pre-run: playbooks/nodepool-tox/pre.yaml
     vars: *nodepool_tox_vars
 
+- job:
+    name: nodepool-tox-py39
+    description: |
+      Nodepool unit tests with ZooKeeper running
+    parent: tox-py39
+    pre-run: playbooks/nodepool-tox/pre.yaml
+    vars: *nodepool_tox_vars
+
 - project:
     vars:
       release_python: python3
@@ -283,6 +291,7 @@
         - tox-pep8
         - nodepool-tox-py36
         - nodepool-tox-py38
+        - nodepool-tox-py39
         - nodepool-zuul-functional:
             voting: false
         - nodepool-functional-container-openstack-release
@@ -300,6 +309,7 @@
         - tox-pep8
         - nodepool-tox-py36
         - nodepool-tox-py38
+        - nodepool-tox-py39
         - nodepool-functional-k8s
         - nodepool-functional-openshift
         - zuul-quick-start:

setup.cfg

@@ -17,6 +17,7 @@ classifier =
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
 
 [pbr]
 warnerrors = True