Checklist

• I've searched the issue queue to verify this is not a duplicate bug report.
• I've included steps to reproduce the bug.
• I've pasted the output of kargo version.
• I've pasted logs, if applicable.

Description

When upgrading to Kargo 1.6.0 Helm throws an error due to a change to an immutable field on kargo-webhooks-server deployment.

Steps to Reproduce

1. Install an earlier version of Kargo (e.g. 1.5.3)
2. Upgrade to Kargo 1.6.0

Logs

Error: UPGRADE FAILED: cannot patch "kargo-webhooks-server" with kind Deployment: Deployment.apps "kargo-webhooks-server" is invalid: spec.selector: Invalid value: v1.LabelSelector{MatchLabels:map[string]string{"app.kubernetes.io/component":"kubernetes-webhooks-server", "app.kubernetes.io/instance":"kargo", "app.kubernetes.io/name":"kargo"}, MatchExpressions:[]v1.LabelSelectorRequirement(nil)}: field is immutable

Workaround is to manually delete the kargo-webhooks-server deployment so the new manifest can be applied.