[7.x] Update API generator for async

elasticsearch/_async/client/migration.py

@@ -0,0 +1,24 @@
+# Licensed to Elasticsearch B.V under one or more agreements.
+# Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+# See the LICENSE file in the project root for more information
+
+from .utils import NamespacedClient, query_params, _make_path
+
+
+class MigrationClient(NamespacedClient):
+    @query_params()
+    def deprecations(self, index=None, params=None, headers=None):
+        """
+        Retrieves information about different cluster, node, and index level settings
+        that use deprecated features that will be removed or changed in the next major
+        version.
+        `<https://www.elastic.co/guide/en/elasticsearch/reference/master/migration-api-deprecation.html>`_
+
+        :arg index: Index pattern
+        """
+        return self.transport.perform_request(
+            "GET",
+            _make_path(index, "_migration", "deprecations"),
+            params=params,
+            headers=headers,
+        )