Update changes log for release.

CHANGES

@@ -1,5 +1,19 @@
 HikariCP Changes
 
+Changes in 2.6.2
+
+ * issue 890 add support for Prometheus metrics and multiple HikariCP pools.
+
+ * issue 880 fix race condition caused by sorting collection while the condition of
+   sort can change.
+
+ * issue 876 add support for using a Prometheus CollectorRegistry other than the
+   default one.
+
+ * issue 867 support network timeout even for Connection.isValid().
+
+ * issue 866 mark commit state dirty when Connection.getMetaData() is called.
+
 Changes in 2.6.1
 
  * issue 821 if a disconnection class exception is thrown during initial connection