Update simplesamlphp/composer-module-installer requirement (#49)

Updates the requirements on [simplesamlphp/composer-module-installer](https://github.com/simplesamlphp/composer-module-installer) to permit the latest version.

Updates `simplesamlphp/composer-module-installer` to 1.4.0
- [Release notes](https://github.com/simplesamlphp/composer-module-installer/releases)
- [Commits](simplesamlphp/composer-module-installer@v1.3.6...v1.4.0)

---
updated-dependencies:
- dependency-name: simplesamlphp/composer-module-installer
  dependency-version: 1.4.0
  dependency-type: direct:production
  dependency-group: production-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

composer.json

@@ -38,7 +38,7 @@
         "ext-libxml": "*",
 
         "simplesamlphp/assert": "~1.8.1",
-        "simplesamlphp/composer-module-installer": "~1.3.6",
+        "simplesamlphp/composer-module-installer": "~1.4.0",
         "simplesamlphp/simplesamlphp": "~2.4.0",
         "simplesamlphp/xml-common": "~1.25.0",
         "symfony/http-foundation": "~6.4.0",