chore: bump version to 5.6.28

[FeiWang1119]

release 5.6.28

Log:

[deepin-ci-robot]

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[github-actions[bot]]

TAG Bot

TAG: 5.6.28 EXISTED: no DISTRIBUTION: unstable

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 检查是否有必要在每次版本更新时都添加新的维护者声明（ maintainer statement），这可能会导致日志过于冗长。
• 确认 maintainer statement 的格式和信息是否符合 Debian 项目的标准。

是否建议立即修改:

• 是，建议根据日志规范和 maintainer statement 的必要性来决定是否保留或修改当前的 maintainer statement。如果 maintainer statement 没有实际的信息或过于冗长，应该考虑移除或简化。

[asterwyx]

https://github.com/linuxdeepin/dtk/pull/176