Update changelog

Author: ocelotl

opentelemetry-sdk/CHANGELOG.md

@@ -10,7 +10,7 @@
   ([#998](https://github.com/open-telemetry/opentelemetry-python/pull/998))
 - Samplers to accept parent Context
   ([#1267](https://github.com/open-telemetry/opentelemetry-python/pull/1267))
-- Add debug Controller and set initial checkpoint timestamp in aggregators
+- Set initial checkpoint timestamp in aggregators
   ([#1237](https://github.com/open-telemetry/opentelemetry-python/pull/1237))
 
 ## Version 0.14b0