Update changelog

Author: aeisenberg

extensions/ql-vscode/CHANGELOG.md

@@ -13,6 +13,7 @@
 - Allow setting `codeQL.runningQueries.numberOfThreads` and `codeQL.runningTests.numberOfThreads` to 0, (which is interpreted as 'use one thread per core on the machine').
 - Clear the problems view of all CodeQL query results when a database is removed.
 - Add a `View DIL` command on query history items. This opens a text editor containing the Datalog Intermediary Language representation of the compiled query.
+- Alter structure of the _Test Explorer_ tree. It now follows the structure of the filesystem instead of the qlpacks.
 
 ## 1.3.3 - 16 September 2020