Update changelog.

CHANGELOG.md

@@ -8,6 +8,7 @@
  - New configuration tree parser
    - Checks configuration parameters more strictly, automatically prints error/warning messages.
    - Requires Boost >= 1.56 because of boost::optional with move semantics.
+ - Command line argument `-l` for OGS cli and testrunner to specify verbosity of logging, #1056
 
 ### Infrastructure