chore(deps): bump express from 4.18.2 to 4.19.2 in /docs/esm (GoogleCloudPlatform#597)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Matthew Robertson <mattrobertson@google.com>

Author: dependabot[bot]