Allow Ws Addressing plugin to use a different URL address than the bi…

…nding address.

Some SOAP services require you to connect to a gateway server but specify your actual url in the addressing part.

With this change you can override the binding address if you want to, but by default it will use the same address.

src/zeep/wsa.py

@@ -13,6 +13,9 @@
 class WsAddressingPlugin(Plugin):
     nsmap = {"wsa": ns.WSA}
 
+    def __init__(self, address_url: str = None):
+        self.address_url = address_url
+
     def egress(self, envelope, http_headers, operation, binding_options):
         """Apply the ws-addressing headers to the given envelope."""
 
@@ -24,7 +27,7 @@ def egress(self, envelope, http_headers, operation, binding_options):
         headers = [
             WSA.Action(wsa_action),
             WSA.MessageID("urn:uuid:" + str(uuid.uuid4())),
-            WSA.To(binding_options["address"]),
+            WSA.To(self.address_url or binding_options["address"]),
         ]
         header.extend(headers)