chore: update changelog

[deepin-ci-robot]

Release 5.6.16.

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: deepin-ci-robot

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

Needs approval from an approver in each of these files: - **[debian/deepin/OWNERS](https://github.com/linuxdeepin/dtkwidget/blob/master/debian/deepin/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[github-actions[bot]]

Permission denied

[github-actions[bot]]

TAG Bot

TAG: 5.6.16 EXISTED: no DISTRIBUTION: unstable

[deepin-bot[bot]]

Doc Check bot :green_circle: Document Coverage Check Passed!

[hudeng-go]

/check obs

[deepin-bot[bot]]

Deepin ChatOps Bot Deepin redeliveried failed, need update or recreate pull request!!!