Don't use Tempdir with system default

[dmikusa]

Summary

Github Actions doesn't have a /tmp directory so this PR switches from using Tempdir to using the present directory for output of the body & name. It then supplies a directory to Tempdir so that it puts the tempfiles into $RUNNER_TEMP for extracting TAR files.

Use Cases

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).