filters clarity

Great Terraform provider! 
This caught me out and thought it was a good idea to make it clear how to use the `filters` block

docs/resources/replication.md

@@ -18,6 +18,22 @@ resource "harbor_replication" "push" {
   action      = "push"
   registry_id = harbor_registry.main.registry_id
 }
+
+resource "harbor_replication" "alpine" {
+  name        = "alpine"
+  action      = "pull"
+  registry_id = harbor_registry.main.registry_id
+  schedule = "* 0/15 * * * *"
+  filters {
+    name = "library/alpine"
+  }
+  filters {
+    tag = "3.*.*"
+  }
+  filters {
+    resource = "image"
+  }
+}
  
 ```
 
@@ -56,4 +72,4 @@ Harbor project can be imported using the `replication id` eg,
 
 `
 terraform import harbor_project.main /registries/7
-`
+`