Yes, it is possible to use GitLab for Tezos. Tezos Commons, the official Tezos organization, provides an official GitLab instance for managing Tezos projects. Arthur Breitman, the creator of Tezos, is an active contributor to the Tezos Commons GitLab instance. You can use the GitLab instance to host and manage your Tezos projects. You can use the same features available on any other GitLab instance, such as source code management, issue tracking, project planning, and more. Additionally, you can also use the Tezos Commons GitLab instance to collaborate with other Tezos developers, as well as to connect with the larger Tezos community.