chore: add pyproject-fmt pre-commit hook

[Saransh-cpp]

Now that vector uses only pyproject.toml for specifying all the build and packaging-related things, I think adding this hook would be a good idea.

[codecov-commenter]

Codecov Report

Merging #230 (60d9384) into main (cac88a2) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #230   +/-   ##
=======================================
  Coverage   82.63%   82.63%           
=======================================
  Files          96       96           
  Lines       10524    10524           
=======================================
  Hits         8697     8697           
  Misses       1827     1827           

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[Saransh-cpp]

I think this should be okay to merge without a review as pyproject-fmt is in the process of being added to Scikit-HEP developer pages - scikit-hep/scikit-hep.github.io#214!