Update simplesamlphp/assert requirement

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

Updates `simplesamlphp/assert` to 1.7.0
- [Release notes](https://github.com/simplesamlphp/assert/releases)
- [Commits](simplesamlphp/assert@v1.6.0...v1.7.0)

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

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

composer.json

@@ -13,7 +13,7 @@
         "ext-dom": "*",
         "ext-spl": "*",
 
-        "simplesamlphp/assert": "~1.6.0",
+        "simplesamlphp/assert": "~1.7.0",
         "simplesamlphp/xml-common": "~1.23.2"
     },
     "require-dev": {