feat: simulate pull request merge and then run deployment

[levibostian]

Stack:

• feat: add support for stacked pull requests #41
• fix: github actions set-output is deprecated #40
• feat: comment on pull requests with the next version of the software, if it deploys #39
• docs: add note about test mode for deployment commands #38
• feat: simulate pull request merge and then run deployment #37 ⬅
• refactor: write all git code to perform a simulated merge #36
• refactor: detect if tool is running in a pull_request or push #35

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

• alpha
  • refactor: detect if tool is running in a pull_request or push #35
    • refactor: write all git code to perform a simulated merge #36
      • feat: simulate pull request merge and then run deployment #37 👈
        • docs: add note about test mode for deployment commands #38
          • feat: comment on pull requests with the next version of the software, if it deploys #39
            • fix: github actions set-output is deprecated #40
              • feat: add support for stacked pull requests #41

[levibostian]

Closing pull request: commit has gone away

[levibostian]

Merged in a different PR #42