fix logger in regards to DebugLoggerInterface
merged branch Tobion/monolog-logger (PR #8040)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #8040).

Discussion
----------

[Monolog] fix logger in regards to DebugLoggerInterface

Commits
-------

438f75c [Monolog] fix logger in regards to DebugLoggerInterface