Bump auth0/auth0-php from 5.7.0 to 7.5.0

Bumps [auth0/auth0-php](https://github.com/auth0/auth0-PHP) from 5.7.0 to 7.5.0.
- [Release notes](https://github.com/auth0/auth0-PHP/releases)
- [Changelog](https://github.com/auth0/auth0-PHP/blob/master/CHANGELOG.md)
- [Commits](auth0/auth0-PHP@5.7.0...7.5.0)

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

composer.json

@@ -21,7 +21,7 @@
         "slim/psr7": "^0.5",
         "symfony/yaml": "^4.3",
         "zendframework/zend-httphandlerrunner": "^1.1",
-        "auth0/auth0-php": "^5.7",
+        "auth0/auth0-php": "^7.5",
         "beberlei/assert": "^3.2",
         "cultuurnet/culturefeed-php": "^1.10",
         "cultuurnet/udb3-api-guard": "^v4.0.0",