Upgrade pypdf lib and fix generation issues

[cmcproject]

• Switch from PyPDF2 -> pypdf
  • The PyPDF2 project is going back to its roots. PyPDF2==3.0.X will be the last version of PyPDF2. Development will continue with pypdf==3.1.0.
• Fix output intents generation
  • getObject is deprecated and was removed. therefore, output intents were missing from the output pdf. get_object shall be used instead
  • it can be checked via https://www.pdf-online.com/osa/validate.aspx
• Fix NameObject generation error; e
  • NameObject error is raised every time you generate an invoice; therefore, replace NameObject with create_string_object for the metadata size field
• Add logging to pdf generation

[codecov]

Codecov Report

Patch coverage: 92.30% and project coverage change: +0.01 🎉

Comparison is base (630dc41) 90.54% compared to head (0450a46) 90.55%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master       #6      +/-   ##
==========================================
+ Coverage   90.54%   90.55%   +0.01%     
==========================================
  Files          17       17              
  Lines        1396     1398       +2     
==========================================
+ Hits         1264     1266       +2     
  Misses        132      132              

Impacted Files	Coverage Δ
drafthorse/pdf.py	92.46% <91.66%> (+0.10%)	⬆️
drafthorse/__init__.py	100.00% <100.00%> (ø)

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