Set controller.strategy for the helm chart will cause error

[wd]

Describe the bug
After setting the controller.strategy in the values file, I'll see this error when running the helm install.

error validating "": error validating data: [apiVersion not set, kind not set]

To Reproduce
Steps to reproduce the behavior:

1. run helm template --set 'controller.strategy.type=OnDelete' deployments/helm-chart/
2. You will see a manifest like below. This is not a valid manifest and can't be applied.

---
# Source: nginx-ingress/templates/controller-daemonset.yaml
updateStrategy:
    type: OnDelete

Expected behavior
That manifest should not be generated.

Your environment

• Version of the Ingress Controller: 2.3.0
• Version of Kubernetes: 1.20
• Kubernetes platform: rke
• Using NGINX or NGINX Plus: Plus

Additional context
I think the issue introduced from this PR #2672.

[github-actions]

Hi @wd thanks for reporting!

Be sure to check out the docs while you wait for a human to take a look at this 🙂

Cheers!