Upgrade cert-manager

cert-manager/.gitignore

@@ -0,0 +1 @@
+cert-manager.yaml

cert-manager/README.md

@@ -5,13 +5,13 @@
 Added manifest with:
 
 ```
-curl -L https://github.com/jetstack/cert-manager/releases/download/v1.6.1/cert-manager.yaml -O
+curl -L https://github.com/jetstack/cert-manager/releases/download/v1.15.1/cert-manager.yaml -O
 ```
 
 To update certificate issuer
 
 ```
-kubectl apply -f namespace.yml -f cert-manager.yaml
+kubectl apply -f cert-manager.yaml
 kubectl apply -f issuer.yml
  kubectl -n cert-manager create secret generic tsig-secret \
     --from-literal=TSIG_SECRET=<secret>