Elixir: update thread count in parr_run

[DeemoONeill]

Description

Fix the threadcount in the parr_run output

Contributing requirements

• [x] I read the contribution guidelines in CONTRIBUTING.md.
• [x] I placed my solution in the correct solution folder.
• [x] I added a README.md with the right badge(s).
• [x] I added a Dockerfile that builds and runs my solution.
• [x] I selected drag-race as the target branch.
• [x] All code herein is licensed compatible with BSD-3.

[rbergen]

Thanks for following this up so quickly. You unequivocally beat me to it. :)

[DeemoONeill]

Apologies for letting it sneak in there in the first place