Update GITLAB_PAGES_VERSION

Main changes:

* Update module golang.org/x/net to v0.20.0
* Add support for domain level redirects
* Update module golang.org/x/sys to v0.16.0
* Update module golang.org/x/sync to v0.6.0
* Update module github.com/prometheus/client_golang to v1.18.0
* Add project prefix in session cookie path

Reference: https://gitlab.com/gitlab-org/gitlab-pages/-/compare/bf6cd6ddf529f8958adee206ac0f93953e9ac39c...852bde8a974154b34f8c3f0bbf42014e69f5a240?from_project_id=734943&straight=false

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This is part of the [Gitlab Pages update process](https://gitlab.com/gitlab-org/gitlab-pages/-/blob/master/PROCESS.md)

Changelog: changed