Improper Sanitization of Branch Name Leads to Arbitrary Code Injection

tj-actions/branch-names is a Github action to retrieve branch or tag names with support for all events. The `tj-actions/branch-names` GitHub Actions improperly references the `github.event.pull_request.head.ref` and `github.head_ref` context variables within a GitHub Actions `run` step. The head ref variable is the branch name and can be used to execute arbitrary code using a specially crafted branch name. As a result an attacker can use this vulnerability to steal secrets from or abuse `GITHUB_TOKEN` permissions. This vulnerability has been addressed in version 7.0.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.