Mczify 1.5.0+2.0+8.16

Compatible with Mathematical Components 2.0 and Coq 8.16 to 8.17. The ssrZ library now provides semiring instances for nat¹ and N, and homomorphism instances for Posz,¹ bin_of_nat, nat_of_bin, N.of_nat, N.to_nat, Z.of_nat, and Z.of_N.

1. These instances will also be included in MathComp from its version 2.1. Thus, we expect to eventually remove them from the Mczify library. ↩ ↩²