x11/walker: Update to 2.9.2

Changelog:

• https://github.com/abenz1267/walker/releases/tag/v2.8.1
• https://github.com/abenz1267/walker/releases/tag/v2.8.2
• https://github.com/abenz1267/walker/releases/tag/v2.9.0
• https://github.com/abenz1267/walker/releases/tag/v2.9.1
• https://github.com/abenz1267/walker/releases/tag/v2.9.2

Reported by: GitHub (watch releases)