build(deps-dev): bump eslint-config-etherpad in /src (#5791)

Bumps [eslint-config-etherpad](https://github.com/ether/eslint-config-etherpad) from 3.0.13 to 3.0.15.
- [Commits](https://github.com/ether/eslint-config-etherpad/compare/v3.0.13...v3.0.15)

---
updated-dependencies:
- dependency-name: eslint-config-etherpad
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

src/package.json

@@ -79,7 +79,7 @@
   },
   "devDependencies": {
     "eslint": "^8.43.0",
-    "eslint-config-etherpad": "^3.0.13",
+    "eslint-config-etherpad": "^3.0.15",
     "etherpad-cli-client": "^2.0.2",
     "mocha": "^10.0.0",
     "mocha-froth": "^0.2.10",