update changelog

Author: YunchuWang

CHANGELOG.md

@@ -1,5 +1,5 @@
 ## placeholder
-* Add automatic proto file download and commit hash tracking during build ([#202](https://github.com/microsoft/durabletask-java/pull/202))
+* Add automatic proto file download and commit hash tracking during build ([#207](https://github.com/microsoft/durabletask-java/pull/207))
 * Fix infinite loop when use continueasnew after wait external event ([#183](https://github.com/microsoft/durabletask-java/pull/183))
 * Fix the issue "Deserialize Exception got swallowed when use anyOf with external event." ([#185](https://github.com/microsoft/durabletask-java/pull/185))