Update changelog for 1.24 release

CHANGES.rst

@@ -4,6 +4,20 @@ Changes
 dev (master)
 ------------
 
+* ... [Short description of non-trivial change.] (Issue #)
+
+
+1.24 (2018-10-16)
+-----------------
+
+* Allow key_server_hostname to be specified when initializing a PoolManager to allow custom SNI to be overridden. (Pull #1449)
+
+* Test against Python 3.7 on AppVeyor. (Pull #1453)
+
+* Early-out ipv6 checks when running on App Engine. (Pull #1450)
+
+* Change ambiguous description of backoff_factor (Pull #1436)
+
 * Add ability to handle multiple Content-Encodings (Issue #1441 and Pull #1442)
 
 * Skip DNS names that can't be idna-decoded when using pyOpenSSL (Issue #1405).
@@ -16,10 +30,10 @@ dev (master)
 * Fixed bug where responses with header Content-Type: message/* erroneously
   raised HeaderParsingError, resulting in a warning being logged. (Pull #1439)
 
-* ... [Short description of non-trivial change.] (Issue #)
+* Move urllib3 to src/urllib3 (Pull #1409)
 
 
-1.23 (2018-06-05)
+1.23 (2018-06-04)
 -----------------
 
 * Allow providing a list of headers to strip from requests when redirecting