[Logging] Fix incorrect PHP example to exclude HTTP code with Monolog

[ker0x]

With the previous example, when running composer run-script --no-dev post-install-cmd we get the following error:

Executing script cache:clear [KO]
 [KO]
Script cache:clear returned with error code 1
!!  
!!  In FileLoader.php line 174:
!!                                                                                 
!!    The following keys are not supported by "Symfony\Config\Monolog\HandlerConf  
!!    ig\ExcludedHttpCodeConfig": 0, 1 in /home/ker0x/dev/imdb/config/packages/pr  
!!    od/monolog.php (which is being imported from "/home/ker0x/dev/imdb/src/Kern  
!!    el.php").                                                                    
!!                                                                                 
!!  
!!  In ExcludedHttpCodeConfig.php line 57:
!!                                                                                 
!!    The following keys are not supported by "Symfony\Config\Monolog\HandlerConf  
!!    ig\ExcludedHttpCodeConfig": 0, 1                                             
!!                                                                                 
!!  
!!  
Script @auto-scripts was called via post-install-cmd

[javiereguiluz]

Good catch, thanks Romain.