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/ircmaxell/security-lib/README.md

@@ -0,0 +1,15 @@
+SecurityLib
+===========
+
+This is a base set of libraries used in other projects. This isn't useful on its own...
+
+
+License
+-------
+
+MIT, see LICENSE.
+
+Security Vulnerabilities
+========================
+
+If you have found a security issue, please contact the author directly at [me@ircmaxell.com](mailto:me@ircmaxell.com).