Use Cache to Avoid Duplicate Workflow Steps

[arielswalker]

Checklist (Please check before submitting)

• [x] I reviewed the Contributing Guide.
• [x] I reviewed the cFS README.md file to see if the feature is in the major future work.
• [x] I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe. RTEMS workflows checks out and builds twice.

Describe the solution you'd like Should use cache to only build once like other cFS build and test workflows.

Describe alternatives you've considered Keep as is.

Requester Info Ariel Walker, MCSG TECH.