Add compat with ChainRulesCore v2

[JamesWrigley]

Tested manually by deving v2 and JuliaDiff/FiniteDifferences.jl#248.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.62%. Comparing base (f7fc032) to head (ff893a5).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #295   +/-   ##
=======================================
  Coverage   95.62%   95.62%           
=======================================
  Files          12       12           
  Lines         343      343           
=======================================
  Hits          328      328           
  Misses         15       15           

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[JamesWrigley]

I did the same integration test fix as in JuliaDiff/FiniteDifferences.jl#248, which should fix the SpecialFunctions integration test. The BlockDiagonals test should be fixed by JuliaArrays/BlockDiagonals.jl#151.