add jsonargparse in requirements

[aniketmaurya]

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

What does this PR do?

jsonargparse was missing in requirements.txt. This PR fixes that.

PR review

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95%. Comparing base (ac0009f) to head (5bad15f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@         Coverage Diff         @@
##           main   #306   +/-   ##
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  Coverage    95%    95%           
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  Files        21     21           
  Lines      1310   1310           
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  Hits       1239   1239           
  Misses       71     71