update docs and bunp changelog

Changelog.rst

@@ -5,6 +5,8 @@ Changelog
 
 6.2.0 (dev)
 -----------
+  * ``_routing`` in bulk action has been deprecated in ES. Introduces a breaking change
+    if you use ``routing`` as a field in your documents.
 
 6.1.1 (2018-01-05)
 ------------------

docs/helpers.rst

@@ -28,7 +28,7 @@ in several formats. The most common one is the same  as returned by
         '_index': 'index-name',
         '_type': 'document',
         '_id': 42,
-        '_parent': 5,
+        'routing': 5,
         'pipeline': 'my-ingest-pipeline',
         '_source': {
             "title": "Hello World!",
@@ -43,7 +43,7 @@ from the doc and use the rest as the document data:
 
     {
         "_id": 42,
-        "_parent": 5,
+        "routing": 5,
         "title": "Hello World!",
         "body": "..."
     }