fix: invalid ingress annotation

With the new ingress controller will the ingress resource be verified
and returns an error like this one:

  Error: Ingress.extensions "drone" is invalid:
  annotations.kubernetes.io/ingress.class: Invalid value: "nginx": can
  not be set when the class field is also set

For this reason the annotation kubernetes.io/ingress.class has been
removed.

values.yaml

@@ -479,10 +479,6 @@ ingress:
   enabled: false
   className: "nginx"
   annotations:
-    # kubernetes.io/ingress.class is a deprecated annotation:
-    # https://kubernetes.io/docs/concepts/services-networking/ingress/#deprecated-annotation
-    kubernetes.io/ingress.class: nginx
-    kubernetes.io/tls-acme: "true"
     # cert-manager.io/issuer: letsencrypt
   hosts:
   - host: "your-hostname"