Bump rxjs from 6.5.4 to 6.6.3

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.5.4 to 6.6.3.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/6.6.3/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.5.4...6.6.3)

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

Author: dependabot[bot]

package-lock.json

@@ -40,7 +40,7 @@
     "@angular/platform-browser-dynamic": "^9.1.0",
     "@angular/router": "^9.1.0",
     "@nrwl/angular": "9.4.5",
-    "rxjs": "~6.5.4",
+    "rxjs": "~6.6.3",
     "zone.js": "^0.10.2"
   },
   "devDependencies": {