Bump the version number to 0.8.12.
Bump the version number to 0.8.12.

Changes since 0.8.11:
- Support building as an external VTK 9 module, with wrapping
- Expand dictionary for latest DICOM CPs

Bug fixes since 0.8.11:
- Fix handling of query files on Windows
- Fix semicolon usage for VTK 9 SetGet macros

dgobbi/vtk-dicom,dgobbi/vtk-dicom,dgobbi/vtk-dicom