Allow running dualstack tests for Go (#152)

v1.71.x is the next release, so that should be the first one that has
the dualstack feature available. This change should allow running the
test against master.

Author: arjan-bal

tests/dualstack_test.py

@@ -49,6 +49,8 @@ def is_supported(config: skips.TestConfig) -> bool:
             return config.version_gte("v1.66.x")
         if config.client_lang == _Lang.NODE:
             return config.version_gte("v1.12.x")
+        if config.client_lang == _Lang.GO:
+            return config.version_gte("v1.71.x")
         return False
 
     @classmethod