v0.6.43

ApproxFunOrthogonalPolynomials v0.6.43

Diff since v0.6.42

Merged pull requests:

• Tests for type-inference in kronecker operator indexing (#288) (@jishnub)
• Unify getindex for ConcreteConversion (#289) (@jishnub)
• Test for DefaultDeriv inference and QuotientSpace (#290) (@jishnub)
• Remove opt0 in downstream tests (#291) (@jishnub)
• ProductFun coefficient tests (#292) (@jishnub)
• Type-stability in polynomial space union (#293) (@jishnub)