Make Algorithms depend on Numerics product instead of RealModule.

[stephentyrone]

The RealModule library product will be removed from Numerics at some future point (the module will continue to exist). Update Package.swift to depend on the Numerics library instead.

Checklist

• I've added at least one test that validates that my change is working, if appropriate
• I've followed the code style of the rest of the project
• I've read the Contribution Guidelines
• I've updated the documentation if necessary

[stephentyrone]

@swift-ci test

[finagolfin]

Thanks, this will unbreak my Android CI.