build(deps): bump express-rate-limit from 6.3.0 to 6.4.0 in /src

Bumps [express-rate-limit](https://github.com/nfriedly/express-rate-limit) from 6.3.0 to 6.4.0.
- [Release notes](https://github.com/nfriedly/express-rate-limit/releases)
- [Changelog](https://github.com/nfriedly/express-rate-limit/blob/master/changelog.md)
- [Commits](https://github.com/nfriedly/express-rate-limit/compare/v6.3.0...v6.4.0)

---
updated-dependencies:
- dependency-name: express-rate-limit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/package-lock.json

@@ -2552,9 +2552,9 @@
       }
     },
     "express-rate-limit": {
-      "version": "6.3.0",
-      "resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-6.3.0.tgz",
-      "integrity": "sha512-932Io1VGKjM3ppi7xW9sb1J5nVkEJSUiOtHw2oE+JyHks1e+AXuOBSXbJKM0mcXwEnW1TibJibQ455Ow1YFjfg=="
+      "version": "6.4.0",
+      "resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-6.4.0.tgz",
+      "integrity": "sha512-lxQRZI4gi3qAWTf0/Uqsyugsz57h8bd7QyllXBgJvd6DJKokzW7C5DTaNvwzvAQzwHGFaItybfYGhC8gpu0V2A=="
     },
     "express-session": {
       "version": "npm:@etherpad/express-session@1.18.1",

src/package.json

@@ -38,7 +38,7 @@
     "etherpad-require-kernel": "^1.0.15",
     "etherpad-yajsml": "0.0.12",
     "express": "4.17.3",
-    "express-rate-limit": "^6.3.0",
+    "express-rate-limit": "^6.4.0",
     "express-session": "npm:@etherpad/express-session@^1.18.1",
     "fast-deep-equal": "^3.1.3",
     "find-root": "1.1.0",