Bump path-to-regexp from 1.8.0 to 1.9.0 in /kolibri/core

Bumps [path-to-regexp](https://github.com/pillarjs/path-to-regexp) from 1.8.0 to 1.9.0.
- [Release notes](https://github.com/pillarjs/path-to-regexp/releases)
- [Changelog](https://github.com/pillarjs/path-to-regexp/blob/master/History.md)
- [Commits](pillarjs/path-to-regexp@v1.8.0...v1.9.0)

---
updated-dependencies:
- dependency-name: path-to-regexp
  dependency-type: direct:production
...

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

kolibri/core/package.json

@@ -25,7 +25,7 @@
     "lockr": "0.8.5",
     "lodash": "^4.17.21",
     "loglevel": "^1.9.2",
-    "path-to-regexp": "1.8.0",
+    "path-to-regexp": "1.9.0",
     "screenfull": "^5.2.0",
     "tinycolor2": "^1.6.0",
     "ua-parser-js": "^1.0.38",