Update pdfbox to 2.0.8

Test new deploy :(

🐛 PDF: Fix NPE for legitimate documents

This was a sad story, that could have been prevented with tests. JUST
SAYIN', dear me!

Release v0.0.6

Release v0.0.5

🔖 Release v0.0.4

🐛 OOXML: Fix regression introduced in 271f1e6

If a part exists without a linked relation, the deletePart method
throws an exception: `throw new IllegalArgumentException("partName");`

This is not the expected behaviour here: malformed files, or partly
sanitized files match this pattern.

Instead, we check if the relationship exists and is in the package.

🔖 Release v0.0.2

Update the readme o/

🎉 First release