Bump rxjs from 6.5.5 to 6.6.0 (#14431)

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.5.5 to 6.6.0.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/6.6.0/CHANGELOG.md)
- [Commits](https://github.com/reactivex/rxjs/compare/6.5.5...6.6.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

yarn.lock

@@ -9559,9 +9559,9 @@ rx-lite@^3.1.2:
   integrity sha1-Gc5QLKVyZl87ZHsQk5+X/RYV8QI=
 
 rxjs@^6.4.0:
-  version "6.5.5"
-  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.5.5.tgz#c5c884e3094c8cfee31bf27eb87e54ccfc87f9ec"
-  integrity sha512-WfQI+1gohdf0Dai/Bbmk5L5ItH5tYqm3ki2c5GdWhKjalzjg93N3avFjVStyZZz+A2Em+ZxKH5bNghw9UeylGQ==
+  version "6.6.0"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.0.tgz#af2901eedf02e3a83ffa7f886240ff9018bbec84"
+  integrity sha512-3HMA8z/Oz61DUHe+SdOiQyzIf4tOx5oQHmMir7IZEu6TMqCLHT4LRcmNaUS0NwOz8VLvmmBduMsoaUvMaIiqzg==
   dependencies:
     tslib "^1.9.0"