deepin: workflow: disable backup-to-gitlabwh

[Avenger-285714]

With the new Prow-based workflow in place, this is redundant.

Link: deepin-community/.github#92
Link: deepin-community/template-repository#21

Reviewed-by: Gary Wang wangzichong@uniontech.com

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please ask for approval from avenger-285714. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 删除的文件 backup-to-gitlab.yml 应该确认是否有替代的配置文件或任务。
• 工作流 backup-to-gitlabwh 的引用使用了 @master 指定了分支，应该确认分支的稳定性。
• 删除工作流后，相关的 secrets 可能不再有效，需要检查是否有其他地方使用这些 secrets。

是否建议立即修改:

• 是，需要确认工作流的删除是否是有意为之，并确保不会影响其他依赖这些工作流的流程。同时，应该检查 secrets 的使用情况，并确保它们在删除工作流后仍然有效。