Bump convict from 6.0.0 to 6.2.3 in /mad-dog

Bumps [convict](https://github.com/mozilla/node-convict) from 6.0.0 to 6.2.3.
- [Release notes](https://github.com/mozilla/node-convict/releases)
- [Changelog](https://github.com/mozilla/node-convict/blob/master/CHANGELOG.md)
- [Commits](mozilla/node-convict@v6.0.0...v6.2.3)

---
updated-dependencies:
- dependency-name: convict
  dependency-type: direct:production
...

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

mad-dog/package.json

@@ -24,7 +24,7 @@
     "@audius/libs": "1.2.111",
     "async-retry": "^1.3.3",
     "axios": "^0.20.0",
-    "convict": "^6.0.0",
+    "convict": "^6.2.3",
     "fs-extra": "^9.0.1",
     "ipfs-unixfs-importer": "^9.0.6",
     "lodash": "^4.17.15",