build(deps): bump mysql2

Bumps the npm_and_yarn group with 1 update in the /container/lighthouse-ci-server directory: [mysql2](https://github.com/sidorares/node-mysql2).


Updates `mysql2` from 2.3.3 to 3.9.7
- [Release notes](https://github.com/sidorares/node-mysql2/releases)
- [Changelog](https://github.com/sidorares/node-mysql2/blob/master/Changelog.md)
- [Commits](https://github.com/sidorares/node-mysql2/compare/v2.3.3...v3.9.7)

---
updated-dependencies:
- dependency-name: mysql2
  dependency-type: direct:production
  dependency-group: npm_and_yarn
...

Signed-off-by: dependabot[bot] <support@github.com>

container/lighthouse-ci-server/package.json

@@ -7,7 +7,7 @@
   "dependencies": {
     "@lhci/cli": "0.13.0",
     "@lhci/server": "0.13.0",
-    "mysql2": "^2.1.0",
+    "mysql2": "^3.9.7",
     "pg": "^8.2.1",
     "pg-hstore": "^2.3.3",
     "sqlite3": "^5.0.0"