fix typo in README.md

[tuduweb]

install requirements should be placed after clone repository.

[codecov]

Codecov Report

Merging #397 (3725a72) into main (3996f81) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #397   +/-   ##
=======================================
  Coverage   74.20%   74.20%           
=======================================
  Files          66       66           
  Lines        4459     4459           
  Branches      756      756           
=======================================
  Hits         3309     3309           
  Misses        970      970           
  Partials      180      180           

Flag	Coverage Δ
unittests	74.20% <ø> (ø)

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[RangiLyu]

Thanks for your contribution!