chore(deps): update cert-manager group to v1.8.1 (patch) (#368)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

cluster/crds/cert-manager/kustomization.yaml

@@ -3,4 +3,4 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
   # renovate: datasource=docker image=quay.io/jetstack/cert-manager-controller
-  - https://github.com/cert-manager/cert-manager/releases/download/v1.8.0/cert-manager.crds.yaml
+  - https://github.com/cert-manager/cert-manager/releases/download/v1.8.1/cert-manager.crds.yaml