Update beste/clock requirement in the production-dependencies group (#84)

Updates the requirements on [beste/clock](https://github.com/beste/clock) to permit the latest version.

Updates `beste/clock` to 4.0.0
- [Release notes](https://github.com/beste/clock/releases)
- [Changelog](https://github.com/beste/clock/blob/4.x/CHANGELOG.md)
- [Commits](beste/clock@3.0.0...4.0.0)

---
updated-dependencies:
- dependency-name: beste/clock
  dependency-version: 4.0.0
  dependency-type: direct:production
  dependency-group: production-dependencies
...

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Author: dependabot[bot]

composer.json

@@ -37,7 +37,7 @@
         "ext-SimpleXML": "*",
         "ext-session": "*",
 
-        "beste/clock": "~3.0",
+        "beste/clock": "~4.0",
         "simplesamlphp/assert": "~2.0",
         "simplesamlphp/composer-module-installer": "~1.7",
         "simplesamlphp/simplesamlphp": "~2.5",