Pull Request Checklist

• Have you added new tests to prevent regressions?
• If a documentation update is necessary, have you opened a PR to the documentation repository?
• Did you update the typescript typings accordingly (if applicable)?
• Does the description below contain a link to an existing issue (Closes #[issue]) or a description of the issue you are solving?
• Does the name of your PR follow our conventions?

Description of Changes

The native legs of test-postgres install pg-native unpinned, so they now pull 3.8.0+, which uses ?? in Client.prototype.getTransactionStatus. Node 10 cannot parse that, require('pg-native') throws at module load, and the four Node 10 native jobs end up running no tests at all.

3.7.0 is the last release Node 10 can read, and pg 8.11.0 (the version the lockfile pins) never calls getTransactionStatus, so pinning it costs nothing here.

Closes #18312

List of Breaking Changes

None.