Prepare for legacy SDK release 2.6.4 GA (#2003)

* Update log4j2

* Update changelog

* Update CHANGELOG.md

* Update CHANGELOG.md

Co-authored-by: Trask Stalnaker <[email protected]>

Author: heyams

CHANGELOG.md

@@ -1,5 +1,9 @@
 # CHANGELOG
 
+# Version 2.6.4
+* Update `applicationinsights-logging-log4j2` artifact to not pull in log4j2 dependency on its own. Users should already be bringing their own version of log4j2 (and should be upgrading that version or applying the mitigation steps from [CVE-2021-44228](https://msrc-blog.microsoft.com/2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/)). The update ensures that users *have* to bring their own version of log4j2.
+  ([#2002](https://github.com/microsoft/ApplicationInsights-Java/issues/2002))
+
 # Version 2.6.3
 * Update xstream dependency [#1580](https://github.com/microsoft/ApplicationInsights-Java/issues/1479)
 * Upgrade gradle from 5.5.1 to 6.8.3

gradle.properties

@@ -1,3 +1,3 @@
 // Project properties
-version=2.6.3
+version=2.6.4
 group=com.microsoft.azure