add kastore to development.txt

[petrelharp]

Closes #2302.

I'm not sure why this is necessary, actually, as kastore is required by tskit. (But I assume that's just because I don't understand how python package management works.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.03%. Comparing base (590a9d5) to head (a83b7dc).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2304   +/-   ##
=======================================
  Coverage   91.03%   91.03%           
=======================================
  Files          20       20           
  Lines       12023    12023           
  Branches     2439     2439           
=======================================
  Hits        10945    10945           
  Misses        595      595           
  Partials      483      483           

Flag	Coverage Δ
C	91.03% <ø> (ø)
python	98.70% <ø> (ø)

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[jeromekelleher]

I don't think the kastore python package is used by tskit, we build the c code for it directly in.