0.7.0

• Support PyQt6 and update packaging (thanks to @PunkPangolin for this work).
• Support PyMuPDF for rendering and cropping.
• Support pikepdf for cropping (thanks to @lianghongzhuo for the idea and initial code).
• Support the new version of pypdf in addition to its predecessor PyPDF2 (thanks to @emmanuelrosa for the idea and initial code).
• Support both old (<2) and new (>=2) versions of PyPDF2 (thanks to @milahu for the idea and initial code).
• When using PyPDF2, preserve links within a PDF (thanks to @chrthi for this).
• Display PDF file name in window title.