chore(3rdparty): update `php-opencloud/openstack` to v3.12.0 for PHP8.4

| Production Changes      | From    | To      | Compare                                                                     |
|-------------------------|---------|---------|-----------------------------------------------------------------------------|
| guzzlehttp/guzzle       | 7.9.2   | 7.9.3   | [...](https://github.com/guzzle/guzzle/compare/7.9.2...7.9.3)               |
| guzzlehttp/promises     | 2.0.4   | 2.2.0   | [...](https://github.com/guzzle/promises/compare/2.0.4...2.2.0)             |
| guzzlehttp/psr7         | 2.7.0   | 2.7.1   | [...](https://github.com/guzzle/psr7/compare/2.7.0...2.7.1)                 |
| guzzlehttp/uri-template | v1.0.3  | v1.0.4  | [...](https://github.com/guzzle/uri-template/compare/v1.0.3...v1.0.4)       |
| php-opencloud/openstack | v3.10.0 | v3.12.0 | [...](https://github.com/php-opencloud/openstack/compare/v3.10.0...v3.12.0) |

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

3rdparty

@@ -1 +1 @@
-Subproject commit f764cac3cb2c6a6fb4945dfdc65c49bfb1d8c42a
+Subproject commit 6a532078f93114f444c65f0ad6a5db1814d52d44