greenshot-unstable: Update to version 1.3.277

[aliesbelik]

• Update to the latest version.
• Fix checkver.

Closes #1590 Closes #1286

• [x] I have read the Contributing Guide.

[github-actions[bot]]

All changes look good.

Wait for review from human collaborators.

greenshot-unstable

• [x] Description
• [x] License
• [x] Hashes
• [x] Checkver
• [x] Autoupdate