build(deps): bump pikepdf from 7.2.0 to 8.5.1

Bumps [pikepdf](https://github.com/pikepdf/pikepdf) from 7.2.0 to 8.5.1.
- [Commits](pikepdf/pikepdf@v7.2.0...v8.5.1)

---
updated-dependencies:
- dependency-name: pikepdf
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>