update to ChainRulesCores 1.0

[mileslucas]

• update to ChainRulesCores 1.0
• add ProjectTo

[codecov]

Codecov Report

Merging #26 (1e6c610) into main (4911a32) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #26      +/-   ##
==========================================
+ Coverage   90.72%   90.75%   +0.02%     
==========================================
  Files          12       12              
  Lines         960      963       +3     
==========================================
+ Hits          871      874       +3     
  Misses         89       89              

Impacted Files	Coverage Δ
src/polynomial/poly-grads.jl	86.11% <100.00%> (+0.05%)	⬆️
src/polynomial/quad-grads.jl	91.66% <100.00%> (+0.07%)	⬆️
src/integrated.jl	93.33% <0.00%> (+0.22%)	⬆️

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