Update Helm release cert-manager to v1.20.2

Author: renovate[bot]

personal-cluster/apps/InfraCertManager.pkl

@@ -25,7 +25,7 @@ source {
   repoURL = "https://charts.jetstack.io"
   chart = "cert-manager"
   // renovate: datasource=helm registryUrl=https://charts.jetstack.io packageName=cert-manager
-  targetRevision = "v1.16.1"
+  targetRevision = "v1.20.2"
   helm {
     releaseName = "cert-manager"
     valuesObject {