science/mpb: Update to 1.12.0

• Add support for anisotropic subpixel smoothing
• Add support for computing mode-overlap integral under symmetry operation
• Disable subpixel smoothing for mesh size of one
• Various minor fixes and additional documentation

All tests passed.

Changelog: https://github.com/NanoComp/mpb/compare/v1.11.1...v1.12.0

Reported by: Repology