chore(deps): enable kustomize manager in Renovate (#4895)

.github/ISSUE_TEMPLATE/release.yaml

@@ -15,16 +15,6 @@ body:
  - patch
  validations:
  required: true
-- type: checkboxes
- id: gateway_version
- attributes:
- label: "Bump Kong Gateway version in manifests"
- options:
- - label: "Note: it might be possible that the latest Gateway version is not compatible with KIC and code changes are required. In such case, a decision whether to release with no compliance with the latest Gateway version should be made on a team level."
- - label: Check the latest minor Kong Gateway release in [Kong releases](https:/Kong/kong/releases).
- - label: Make sure the image tag in [config/image/enterprise/kustomization.yaml](/Kong/kubernetes-ingress-controller/blob/main/config/image/enterprise/kustomization.yaml) and [config/image/oss/kustomization.yaml](/Kong/kubernetes-ingress-controller/blob/main/config/image/oss/kustomization.yaml) is updated accordingly.
- - label: Run `make manifests` to regenerate manifests using the modified kustomizations and open a PR with the changes (similarly to [this PR](https:/Kong/kubernetes-ingress-controller/pull/3288)).
- - label: "Make sure that effective versions configured in manifests of github workflows updated, including these files: .github.com/workflows/e2e_nightly.yaml, .github/workflows/test_nightly.yaml."
 - type: checkboxes
  id: release_branch
  attributes:

renovate.json

@@ -1,7 +1,7 @@
 {
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "configMigration": true,
- "enabledManagers": ["regex"],
+ "enabledManagers": ["regex", "kustomize"],
  "automerge": false,
  "separateMinorPatch": true,
  "labels": ["dependencies"],