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/smolblog/oauth2-twitter/CHANGELOG.md

@@ -0,0 +1,23 @@
+# Changelog #
+
+This project uses [semantic versioning](https://semver.org).
+
+## Version 1
+
+### 1.0.0
+
+- Initial release
+
+### 1.0.1
+
+- Correctly return error description ([PR #2](https://github.com/smolblog/oauth2-twitter/pull/2))
+
+### 1.1.0
+
+- Fix a license mismatch (#4)
+- Add user profile image to the default user (#5)
+- Update README to reflect state of Twitter API and this library
+
+### 1.2.0
+
+- Add user email to the default user