Update simplesamlphp/assert requirement

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

Updates `simplesamlphp/assert` to 2.0.1
- [Release notes](https://github.com/simplesamlphp/assert/releases)
- [Commits](simplesamlphp/assert@v1.9.0...v2.0.1)

---
updated-dependencies:
- dependency-name: simplesamlphp/assert
  dependency-version: 2.0.1
  dependency-type: direct:production
  dependency-group: production-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -16,7 +16,7 @@
         "ext-openssl": "*",
         "ext-pdo": "*",
 
-        "simplesamlphp/assert": "^1.9",
+        "simplesamlphp/assert": "^2.0",
         "simplesamlphp/simplesamlphp": "^2.5@dev"
     },
     "require-dev": {