build(deps): bump winston from 3.14.2 to 3.15.0

Bumps [winston](https://github.com/winstonjs/winston) from 3.14.2 to 3.15.0.
- [Release notes](https://github.com/winstonjs/winston/releases)
- [Changelog](https://github.com/winstonjs/winston/blob/master/CHANGELOG.md)
- [Commits](winstonjs/winston@v3.14.2...v3.15.0)

---
updated-dependencies:
- dependency-name: winston
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -23,7 +23,7 @@
     "geoip-lite": "^1.2.0",
     "ioredis": "^5.4.1",
     "jsonschema": "^1.1.0",
-    "winston": "^3.2.1"
+    "winston": "^3.15.0"
   },
   "devDependencies": {
     "chai": "^4.2.0",