Documentation/Clarity

[aaronlippold]

In reading through the README a few things came to mind

• Document how the with fuction works and what path is relative to
• Example of how you might generate an output file from one task and use it in our action
• Document how you take the result and save it to a desired location
• Let's make one where we convert from one format to another and save it

This is one use case

- name: Display our ${{ matrix.suite }} results summary
    uses: mitre/saf_action@v1
    with:
      command_string: 'view:summary -i spec/results/ec2_rhel-7_${{ matrix.suite }}.json'
 - name: Ensure the scan meets our ${{ matrix.suite }} results threshold
    uses: mitre/saf_action@v1
    with:
      command_string: 'validate:threshold -i spec/results/ec2_rhel-7_${{ matrix.suite }}.json -F ${{ matrix.suite }}.threshold.yml'
 - name: Save Test Result JSON
    uses: actions/upload-artifact@v2
    with:
      path: spec/results/