Update changelog for release

Author: tjwatson

scr/changelog.txt

@@ -1,4 +1,4 @@
-Changes in 2.2.15
+Changes in 2.2.16
 -----------------
 ** Improvement
     * Document Satisfying Condition feature as OSGi R8 specification-compliant
@@ -7,6 +7,7 @@ Changes in 2.2.15
       - See https://docs.osgi.org/specification/osgi.cmpn/8.0.0/service.component.html#service.component-satisfying.condition
       - Added comprehensive documentation in README.md
       - Updated code comments to reflect specification compliance
+    * #486 Stop flooding the scheduled executor with no-op tasks for change count updates
 
 Changes in 2.2.14
 -----------------