Drupal 9 Deprecated Code Report

Problem/Motivation

drupal-check output:

drupal-check web/modules/contrib/language_cookie 
 20/20 [▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓] 100%

 ------ ---------------------------------------------------------------------- 
  Line   src/EventSubscriber/LanguageCookieSubscriber.php                      
 ------ ---------------------------------------------------------------------- 
  166    Call to deprecated constant REQUEST_TIME: Deprecated in drupal:8.3.0  
         and is removed from drupal:9.0.0. Use                                 
         \Drupal::time()->getRequestTime();                                    
 ------ ---------------------------------------------------------------------- 

 ------ -------------------------------------------------------------------------------- 
  Line   src/Plugin/LanguageCookieCondition/LanguageCookieConditionBlacklistedPaths.php  
 ------ -------------------------------------------------------------------------------- 
  73     Parameter $alias_manager of method                                              
         Drupal\language_cookie\Plugin\LanguageCookieCondition\LanguageCookieC           
         onditionBlacklistedPaths::__construct() has typehint with deprecated            
         interface Drupal\Core\Path\AliasManagerInterface:                               
         in drupal:8.8.0 and is removed from drupal:9.0.0.                               
         Use \Drupal\path_alias\AliasManagerInterface.                                   
  109    Call to deprecated method strtolower() of class                                 
         Drupal\Component\Utility\Unicode:                                               
         in drupal:8.6.0 and is removed from drupal:9.0.0. Use                           
         mb_strtolower() instead.                                                        
 ------ -------------------------------------------------------------------------------- 

 ------ ----------------------------------------------------------------------------------------- 
  Line   src/Plugin/LanguageCookieCondition/LanguageCookieConditionHardcodedBlacklistedPaths.php  
 ------ ----------------------------------------------------------------------------------------- 
  83     Parameter $alias_manager of method                                                       
         Drupal\language_cookie\Plugin\LanguageCookieCondition\LanguageCookieC                    
         onditionHardcodedBlacklistedPaths::__construct() has typehint with                       
         deprecated interface Drupal\Core\Path\AliasManagerInterface:                             
         in drupal:8.8.0 and is removed from drupal:9.0.0.                                        
         Use \Drupal\path_alias\AliasManagerInterface.                                            
  129    Call to deprecated method strtolower() of class                                          
         Drupal\Component\Utility\Unicode:                                                        
         in drupal:8.6.0 and is removed from drupal:9.0.0. Use                                    
         mb_strtolower() instead.                                                                 
 ------ ----------------------------------------------------------------------------------------- 

                                                                                
 [ERROR] Found 5 errors                                                         
                                                                               

Deprecations after running tests:

Remaining tasks

• Fix deprecations listed above.
• Add core_version_requirement to language_cookie.info.yml