Polymake.jl 0.11.13 released

Today Polymake.jl 0.11.13 has been released.

Diff since v0.11.12

Merged pull requests:

• allow passing nothing for undef values, update github actions (#469) (@benlorenz)
• mcf: add workaround to avoid hang during tropical median (#471) (@benlorenz)

Closed issues:

• CI: update to codecov/codecov-action@v4 (#470)