misc/shimmy: update to 1.7.0

While here, disable VULKAN option on i386 platform because it causes
"out of memory" error during build.

Changelog:

• https://github.com/Michael-A-Kuykendall/shimmy/releases/tag/v1.6.0
• https://github.com/Michael-A-Kuykendall/shimmy/releases/tag/v1.7.0

Reported by: GitHub (watch releases)