Set the default value of entries to empty list

Without this helm list gives the following warnings:
`coalesce.go:199: warning: cannot overwrite table with non table for entries (map[])
coalesce.go:199: warning: cannot overwrite table with non table for entries (map[])
coalesce.go:199: warning: cannot overwrite table with non table for entries (map[])
coalesce.go:199: warning: cannot overwrite table with non table for entries (map[])
coalesce.go:199: warning: cannot overwrite table with non table for entries (map[])`

Author: ashishkf

helm/oauth2-proxy/values.yaml

@@ -259,7 +259,7 @@ httpScheme: http
 htpasswdFile:
   enabled: false
   existingSecret: ""
-  entries: {}
+  entries: []
   # One row for each user
   # example:
   # entries: