fix(cert-manager): upgrade ClusterIssuer APIs

Author: themightychris

cert-manager.issuers.yaml

@@ -1,4 +1,4 @@
-apiVersion: cert-manager.io/v1alpha2
+apiVersion: cert-manager.io/v1
 kind: ClusterIssuer
 metadata:
   name: letsencrypt-staging
@@ -14,7 +14,7 @@ spec:
           class: nginx
 ---
 
-apiVersion: cert-manager.io/v1alpha2
+apiVersion: cert-manager.io/v1
 kind: ClusterIssuer
 metadata:
   name: letsencrypt-prod