fix(deps): update dependency mysql2 to v3

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

packages/backend/package.json

@@ -93,7 +93,7 @@
     "express-prom-bundle": "^7.0.0",
     "express-promise-router": "^4.1.0",
     "luxon": "^3.0.0",
-    "mysql2": "^2.2.5",
+    "mysql2": "^3.0.0",
     "pg": "^8.11.3",
     "pg-connection-string": "^2.3.0",
     "prom-client": "^15.0.0",