Repository: linode/linode_api4-python

Issue:
`proxy_protocol` on `NodeBalancerConfig` is missing
[Official API documentation](https://www.linode.com/docs/api/nodebalancers/#config-create) says that there is a `proxy_protocol` field on `NodeBalancerConfig`.  Trying to get/set one with `linode_api4` causes:
```
  File "python3.9/site-packages/linode_api4/objects/base.py", line 135, in __getattribute__
    return object.__getattribute__(self, name)
AttributeError: 'NodeBalancerConfig' object has no attribute 'proxy_protocol'
```

Discussion:

Patch:
diff --git a/linode_api4/objects/nodebalancer.py b/linode_api4/objects/nodebalancer.py
index b56b6c0..7a3ec1b 100644
--- a/linode_api4/objects/nodebalancer.py
+++ b/linode_api4/objects/nodebalancer.py
@@ -65,6 +65,7 @@ class NodeBalancerConfig(DerivedBase):
         "ssl_fingerprint": Property(),
         "cipher_suite": Property(mutable=True),
         "nodes_status": Property(),
+        'proxy_protocol': Property(mutable=True),
     }
 
     @property


Test patch:
diff --git a/test/fixtures/nodebalancers_123456_configs.json b/test/fixtures/nodebalancers_123456_configs.json
index 9676abb..f12f134 100644
--- a/test/fixtures/nodebalancers_123456_configs.json
+++ b/test/fixtures/nodebalancers_123456_configs.json
@@ -22,7 +22,8 @@
         "down": 0
       },
       "protocol": "http",
-      "ssl_fingerprint": ""
+      "ssl_fingerprint": "",
+      "proxy_protocol": "none"
     }
   ],
   "results": 1,
diff --git a/test/objects/nodebalancers_test.py b/test/objects/nodebalancers_test.py
index e919495..e78934a 100644
--- a/test/objects/nodebalancers_test.py
+++ b/test/objects/nodebalancers_test.py
@@ -37,6 +37,7 @@ class NodeBalancerConfigTest(ClientBaseCase):
         self.assertEqual(config.nodes_status.up, 0)
         self.assertEqual(config.nodes_status.down, 0)
         self.assertEqual(config.ssl_fingerprint, "")
+        self.assertEqual(config.proxy_protocol, "none")
 
 
 class NodeBalancerNodeTest(ClientBaseCase):