Small edits to the Soak Tests

[NathanielRN]

Description

Follow up to #27, we make some small edits to the Soak Tests:

1. Delete oldest snapshots in the commits/<current_commit_id>/runs/ folder as well as the commits/ folder.
2. With Support repo.repo and repo.owner as template variables JasonEtco/create-an-issue#114 merged, we can use the upstream JasonEtco/create-an-issue action again! (This will be broken until the next minor release)