Upgrade minimum 6.x release for Elasticsearch to 6.4.0

Fix doc and test on ES6 python client compat

This commit changes the statement that version < 6.3.1 of the
elasticsearch python client should be used to instead state
that 6.4.0 is fine.

It also update the tests to reflect the statement.

Initially the `update_all_types` argument has been used to work
around an issue described in:
https://github.com/wagtail/wagtail/issues/2968

This argument was removed in elasticsearch-py 6.3.1 and making
use of it was raising an error.

With 6.4.0 nothing is raising anymore.

CHANGELOG.txt

@@ -7,6 +7,7 @@ Changelog
  * Added `construct_page_listing_buttons` hook (Michael van Tellingen)
  * Added more detailed documentation and troubleshooting for installing OpenCV for feature detection (Daniele Procida)
  * Move and refactor upgrade notification JS (Jonny Scholes)
+ * Remove need for Elasticsearch `update_all_types` workaround, upgrade minimum release to 6.4.0 or above (Jonathan Liuti)
  * Fix: Added line breaks to long filenames on multiple image / document uploader (Kevin Howbrook)
  * Fix: Added https support for Scribd oEmbed provider (Rodrigo)
  * Fix: Changed StreamField group labels color so labels are visible (Catherine Farman)

CONTRIBUTORS.rst

@@ -386,6 +386,7 @@ Contributors
 * Rodrigo
 * Iman Syed
 * John Carter
+* Jonathan Liuti
 
 Translators
 ===========

docs/releases/2.7.rst

@@ -13,6 +13,7 @@ Wagtail 2.7 is designated a Long Term Support (LTS) release. Long Term Support r
 What's new
 ==========
 
+* Upgraded Elasticsearch client library dependency to 6.4.0 or above, 7.0.0 or above is still supported.
 
 Other features
 ~~~~~~~~~~~~~~
@@ -20,6 +21,7 @@ Other features
  * Added ``construct_page_listing_buttons`` hook (Michael van Tellingen)
  * Added more detailed documentation and troubleshooting for installing OpenCV for feature detection (Daniele Procida)
  * Move and refactor upgrade notification JS (Jonny Scholes)
+ * Remove need for Elasticsearch ``update_all_types`` workaround, upgrade minimum release to 6.4.0 or above (Jonathan Liuti)
 
 
 Bug fixes

docs/topics/search/backends.rst

@@ -113,11 +113,12 @@ Prerequisites are the `Elasticsearch`_ service itself and, via pip, the `elastic
 
 .. code-block:: sh
 
-  pip install "elasticsearch>=6.0.0,<6.3.1"  # for Elasticsearch 6.x
+  pip install "elasticsearch>=6.4.0,<7.0.0"  # for Elasticsearch 6.x
 
 .. warning::
 
-    | Version 6.3.1 of the Elasticsearch client library is incompatible with Wagtail. Use 6.3.0 or earlier.
+    | Version 6.3.1 of the Elasticsearch client library is incompatible with Wagtail. Use 6.4.0 or above.
+
 
 The backend is configured in settings:
 

tox.ini

@@ -53,7 +53,7 @@ deps =
     elasticsearch2: elasticsearch>=2,<3
     elasticsearch5: elasticsearch>=5,<6
     elasticsearch5: certifi
-    elasticsearch6: elasticsearch>=6,<6.3.1
+    elasticsearch6: elasticsearch>=6.4.0,<7
     elasticsearch6: certifi
 
 setenv =