Add Symfony Deprecation Contracts package

- Created CHANGELOG.md to maintain version history.
- Added README.md with usage instructions for the trigger_deprecation() function.
- Initialized composer.json for the Symfony Deprecation Contracts library, specifying dependencies and autoloading.

modules/pshowsso/vendor/composer/installed.php

@@ -159,7 +159,7 @@
         'prestashow/presta-core' => array(
             'pretty_version' => 'dev-master',
             'version' => 'dev-master',
-            'reference' => 'cfef8ce2507bc27d9c22920684ddcd067311797a',
+            'reference' => '39712e7efb30c82b3c98a1808f7b5d55c6bbcae9',
             'type' => 'composer-plugin',
             'install_path' => __DIR__ . '/../prestashow/presta-core',
             'aliases' => array(