root/pypi: links for sage-numerical-backends-gurobi

root/pypi sage_numerical_backends_gurobi-10.4.tar.gz
root/pypi sage_numerical_backends_gurobi-10.4rc1.tar.gz
root/pypi sage_numerical_backends_gurobi-9.3.1.tar.gz
root/pypi sage_numerical_backends_gurobi-9.0.0.tar.gz
root/pypi sage_numerical_backends_gurobi-9.0b12.tar.gz
root/pypi sage_numerical_backends_gurobi-9.0b9.tar.gz