Maximize parallelization

[glhewett]

Each of the runners run with multiple cores. We should maximize the use of all of the cores. In the document below, the number of cores are documented. Each build step should have a --parallel argument to specify the number of cores to build with.

From the information provide, we should target having (number of cores + 1) threads. Since linux and windows only have 2 cores, we should use 3 parallel executions. MacOs will utilize all 3 of its cores with that value as well.

ref: https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources