Support readonly arrays in adaptive

[svank]

@astrofrog This is what I found for readonly arrays in Cython: cython/cython#1869

Just need to add const to the types of the input arrays

Closes #449 ?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.52%. Comparing base (0860f9f) to head (e9620c8).
Report is 43 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #452      +/-   ##
==========================================
+ Coverage   91.27%   91.52%   +0.25%     
==========================================
  Files          25       25              
  Lines        1066     1027      -39     
==========================================
- Hits          973      940      -33     
+ Misses         93       87       -6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[svank]

Not sure about the test failures---I think they're unrelated?

[astrofrog]

Yes the failures are unrelated - thanks!