Support validating approvers before applying

[suzuki-shunsuke]

Feature Overview

This issue proposes the feature to validate approvers before running terraform apply.
If no one other than pr's commit authors doesn't approve the pr, tfaction fails.

Why is the feature needed?

This feature needs to follow the policy All changes must be reviewed.
Even if we configure branch protection rules and branch rule set properly, people can violate this policy:

• People can add commits to prs created by bots (GitHub Apps) and approve themselves
  • follow up prs
  • Renovate
• People can add commits to prs created by others and approve themselves
  • Malicious people can abuse stale prs

Example Code

tfaction-root.yaml

validate_approvers: true

Note

No response