Bumped mysqlclient requirement to >= 1.3.13.

There are test failures with older versions.

django/db/backends/mysql/base.py

@@ -32,8 +32,8 @@ from .schema import DatabaseSchemaEditor                    # isort:skip
 from .validation import DatabaseValidation                  # isort:skip
 
 version = Database.version_info
-if version < (1, 3, 7):
-    raise ImproperlyConfigured('mysqlclient 1.3.7 or newer is required; you have %s.' % Database.__version__)
+if version < (1, 3, 13):
+    raise ImproperlyConfigured('mysqlclient 1.3.13 or newer is required; you have %s.' % Database.__version__)
 
 
 # MySQLdb returns TIME columns as timedelta -- they are more like timedelta in

docs/ref/databases.txt

@@ -335,7 +335,7 @@ Connector/Python includes `its own`_.
 mysqlclient
 ~~~~~~~~~~~
 
-Django requires `mysqlclient`_ 1.3.7 or later.
+Django requires `mysqlclient`_ 1.3.13 or later.
 
 MySQL Connector/Python
 ~~~~~~~~~~~~~~~~~~~~~~

docs/releases/2.2.txt

@@ -424,6 +424,9 @@ Miscellaneous
 
 * Support for ``cx_Oracle`` < 6.0 is removed.
 
+* The minimum supported version of ``mysqlclient`` is increased from 1.3.7 to
+  1.3.13.
+
 * In an attempt to provide more semantic query data, ``NullBooleanSelect`` now
   renders ``<option>`` values of ``unknown``, ``true``, and ``false`` instead
   of ``1``, ``2``, and ``3``. For backwards compatibility, the old values are

tests/requirements/mysql.txt

@@ -1,2 +1 @@
-# Due to a bug that will be fixed in mysqlclient 1.3.7.
-mysqlclient >= 1.3.7
+mysqlclient >= 1.3.13