chore(deps): update helm release cert-manager to v1.20.0

Author: renovate[bot]

clusters/home-cluster/cert-manager/helmrelease.yaml

@@ -9,7 +9,7 @@ spec:
     spec:
       # renovate: registryUrl=https://charts.jetstack.io
       chart: cert-manager
-      version: v1.19.2
+      version: v1.20.0
       sourceRef:
         kind: HelmRepository
         name: jetstack