Lifting PyMuPDF's version pin from requirements.txt

[PythonTryHard]

Considering PyMuPDF is only used to open PDFs, is it necessary to hard pin the dependency to 1.19.0 as seen here and here?

In addition, should README.md and Quickstart.md add the steps to troubleshoot PyMuPDF's installation should pre-built wheels be unavailable? By hard-pinning, sooner or later the troubleshooting for PyMuPDF is gonna come as people move to newer Python versions, and 1.19.0 not supporting pre-built wheels past 3.10 means as Python moves forwards, more people will complain about pip install error as the average user expect a plug-and-play experience of pre-built wheels (as per the spirit of the Quickstart's effectively 3 lines to start OCRing), rather having to download compile tools and compile from scratch or install PyMuPDF; and that is assuming people actually spend time to read the error log and understanding it, with "people" referring to "the average user", not "someone deep into Python".

@an1018 as the one that authored 1a9926a introducing PyMuPDF as dependency. Yes, dependency pinning is good software writing techniques, but considering its use in code, what's your opinion? Do we:

• Lift the == completely (i.e., PyMuPDF)?
• Pin against major version bump (PyMuPDF="^1.20.0" or PyMuPDF<2.0.0)?
• Pin against minor version bumps (PyMuPDF="~1.20.0" or PyMuPDF<1.21.0)?

while taking into account that PyMuPDF 1.21.0's pre-built wheel for 3.11 is in consideration upstream?

[an1018]

Thanks for your sincere suggestion. We will modify it later.

[PythonTryHard]

That would be lovely. Thank you for your consideration.