Polymake.jl 0.9.0 released

Today Polymake.jl 0.9.0 has been released.

Diff since v0.8.3

Closed issues:

• Error importing package in wsl. (#417)

Merged pull requests:

• Allow using Mongoc 0.8.x (#418) (@fingolfin)
• Allow CxxWrap 0.13 (#419) (@fingolfin)
• wslview: make configuration more robust (#420) (@benlorenz)
• wrapped vectors and matrices over polynomials (#421) (@alexej-jordan)