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/deps/guzzlehttp/guzzle/package-lock.json

@@ -0,0 +1,6 @@
+{
+  "name": "guzzle",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {}
+}