Summary

This PR is part of our higher-level goal of removing dependencies causing issues for M1/arm64 developers (see #6442).

Our nodegit dependency is only used during our release script. While there are alpha versions of nodegit that purport to support M1, I spiked out removing/replacing the dependency totally with exec versions of git CLI commands, and was able to successful find their corresponding CLI APIs which I found easy enough to replace.

While these changes may not be totally bullet or bug proof, these changes are dev-only and I feel confident enough to move forward with them as-is and fix any issues that arise during the next release.

QA

Release script

• Run npm run release and confirm it outputs the following message: Unable to release: currently on branch "nodegit", expected "main"

Tokens script

• Run node scripts/update-token-changelog.js major and confirm it outputs "No i18n token changes found to commit"
• Open i18ntokens.json and change the first defString to (e.g.) TEST. Save (without Prettier formatting)
• Run node scripts/update-token-changelog.js major and confirm it outputs "i18n token changes committed"
• Run git log and confirm you see an update i18ntokens commit
• Run git reset HEAD^ and inspect the changed files/diff, and confirm i18ntokens_changelog.json looks like this:

  {
    "version": "72.0.0",
    "changes": [
      {
        "token": "euiAccordion.isLoading",
        "changeType": "modified",
        "value": "TEST"
      }
    ]
  },

General checklist

N/A, dev only