Release: v2.1.8 (#467)

## What's Changed
* Update TROUBLESHOOTING.md by @sethvargo in
https://github.com/google-github-actions/auth/pull/457
* fix: add runs-on to README.md example by @lbarthon in
https://github.com/google-github-actions/auth/pull/460
* security: bump undici from 5.28.4 to 5.28.5 in the npm_and_yarn group
by @dependabot in https://github.com/google-github-actions/auth/pull/463
* Update deps by @sethvargo in
https://github.com/google-github-actions/auth/pull/466

## New Contributors
* @lbarthon made their first contribution in
https://github.com/google-github-actions/auth/pull/460

**Full Changelog**:
https://github.com/google-github-actions/auth/compare/v2.1.7...v2.1.8