Update changelog (#748)

* update changelog

Author: dhaval24

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Adds `WebAppNameContextInitializer` for use with the `WebRequestTrackingFilter`.
 - Adds `LocalForwarderChannel` for use with the [LocalForwarder](https://github.com/Microsoft/ApplicationInsights-LocalForwarder).
 - Removes Servlet 3.0 annotations from `WebRequestTrackingFilter` and `ApplicationInsightsServletContextListener` which were causing issues in certain cases. This will allow easier customization of the filter. To use the listener moving forward, it will need to be defined in web.xml. 
+- Fix QuickPulse post interval bug from 5 seconds to 1 second.
 
 # Version 2.1.2
 - Fix [#676](https://github.com/Microsoft/ApplicationInsights-Java/issues/676). This fixes the HTTP dependency collection when using NetFlix Zuul Library.