add lets encrypt staging issuer

clusters/ontime-dev/configs/issuer.yaml

@@ -0,0 +1,13 @@
+apiVersion: cert-manager.io/v1
+kind: Issuer
+metadata:
+  name: lets-encrypt-staging
+spec:
+  acme:
+    server: https://acme-staging-v02.api.letsencrypt.org/directory
+    privateKeySecretRef:
+      name: lets-encrypt-staging-account-key
+    solvers:
+    - http01:
+        ingress:
+          ingressClassName: nginx