Remove NGINX's `isControllerTagValid` helper

Removes NGINX's `isControllerValid` helper, as the check had not been
updated since its implementation in 2020. Additionally, as part of
#3383, we'll need
to refer to a tag that includes `ubi`, which would break the
`semverCompare` function.

Changelog: removed

charts/nginx-ingress/templates/_helpers.tpl

@@ -121,15 +121,6 @@ Return the appropriate apiGroup for PodSecurityPolicy.
 {{- end -}}
 {{- end -}}
 
-{{/*
-Check the ingress controller version tag is at most three versions behind the last release
-*/}}
-{{- define "isControllerTagValid" -}}
-{{- if not (semverCompare ">=0.27.0-0" .Values.controller.image.tag) -}}
-{{- fail "Controller container image tag should be 0.27.0 or higher" -}}
-{{- end -}}
-{{- end -}}
-
 {{/*
 IngressClass parameters.
 */}}

charts/nginx-ingress/templates/controller-daemonset.yaml

 {{- if or (eq .Values.controller.kind "DaemonSet") (eq .Values.controller.kind "Both") -}}
-{{- include  "isControllerTagValid" . -}}
 apiVersion: apps/v1
 kind: DaemonSet
 metadata:

charts/nginx-ingress/templates/controller-deployment.yaml

 {{- if or (eq .Values.controller.kind "Deployment") (eq .Values.controller.kind "Both") -}}
-{{- include  "isControllerTagValid" . -}}
 apiVersion: apps/v1
 kind: Deployment
 metadata:

doc/charts/nginx/fork.md

@@ -26,3 +26,7 @@ The following adjustments were made to the NGINX fork:
   - Add `podlabels` and `global.pod.labels` to `.spec.template.metadata.labels`
 - Disable NGINX's default nodeSelectors.
 - Added support for PDB `maxUnavailable`.
+- Remove NGINX's `isControllerTagValid` helper in `charts/nginx-ingress/templates/_helpers.tpl`
+  - The check had not been updated since it was [implemented](https://github.com/kubernetes/ingress-nginx/pull/5252) in 2020.
+  - As part of [#3383](https://gitlab.com/gitlab-org/charts/gitlab/-/issues/3383), we need to refer to a tag that will contain `ubi`,
+    meaning that the `semverCompare` would not work as expected anyway.