Bump rxjs from 6.5.3 to 7.3.0

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.5.3 to 7.3.0.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/master/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.5.3...7.3.0)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -16,7 +16,7 @@
   },
   "dependencies": {
     "detect-browser": "^4.8.0",
-    "rxjs": "^6.5.3",
+    "rxjs": "^7.3.0",
     "semver-compare": "^1.0.0",
     "socket.io-client": "2.3.0"
   },