x11/nwg-look: update to 1.0.6

While here, switch to GO_MODULE.

Changelog:

• https://github.com/nwg-piotr/nwg-look/releases/tag/v1.0.4
• https://github.com/nwg-piotr/nwg-look/releases/tag/v1.0.5
• https://github.com/nwg-piotr/nwg-look/releases/tag/v1.0.6

Reported by: Repology