Fixes#3356
1.16 removes some api groups that were already deprecated. From k8s blog
post (https://kubernetes.io/blog/2019/07/18/api-deprecations-in-1-16/):
```
- PodSecurityPolicy: will no longer be served from extensions/v1beta1 in
v1.16.
Migrate to the policy/v1beta1 API, available since v1.10. Existing
persisted data can be retrieved/updated via the policy/v1beta1 API.
- DaemonSet, Deployment, StatefulSet, and ReplicaSet: will no longer be
served from extensions/v1beta1, apps/v1beta1, or apps/v1beta2 in v1.16.
Migrate to the apps/v1 API, available since v1.9. Existing persisted
data can be retrieved/updated via the apps/v1 API.
```
Previous PRs had already made this change at the Helm templates level,
but we still needed to do it at the API calls and tests.
The integration tests ran fine for k8s 1.12 and 1.15. They fail on 1.16
because the upgrade integration test tries to install linkerd 2.5 which is not
compatible with 1.16.
Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>