Log Message:
tex-graphics-def{,-doc}: update to 2021.63019

- Use color stacks with (x)dvipdfmx
- Update to fix bounding box for included bitmap images with the dvisvgm driver
- Update to dvisvgm.def to improve pstricks support
- Update to graphics-def with a minor update to dvisvgm.def
  adding .pdf to the list of default extensions.