build: bump rxjs from 6.6.3 to 6.6.6 (#22033)

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.6.3 to 6.6.6.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/6.6.6/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.6.3...6.6.6)

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

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

Author: dependabot[bot]

yarn.lock

@@ -11432,7 +11432,7 @@ rxjs-tslint-rules@^4.33.1:
     tsutils "^3.0.0"
     tsutils-etc "^1.2.2"
 
-[email protected], rxjs@^6.4.0, rxjs@^6.5.3, rxjs@^6.6.0, rxjs@^6.6.2:
+[email protected]:
   version "6.6.3"
   resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.3.tgz#8ca84635c4daa900c0d3967a6ee7ac60271ee552"
   integrity sha512-trsQc+xYYXZ3urjOiJOuCOa5N3jAZ3eiSpQB5hIT8zGlL2QfnHLJ2r7GMkBGuIausdJN1OneaI6gQlsqNHHmZQ==
@@ -11446,6 +11446,13 @@ rxjs@^5.5.6:
   dependencies:
     symbol-observable "1.0.1"
 
+rxjs@^6.4.0, rxjs@^6.5.3, rxjs@^6.6.0, rxjs@^6.6.2:
+  version "6.6.6"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.6.tgz#14d8417aa5a07c5e633995b525e1e3c0dec03b70"
+  integrity sha512-/oTwee4N4iWzAMAL9xdGKjkEHmIwupR3oXbQjCKywF1BeFohswF3vZdogbmEF6pZkOsXTzWkrZszrWpQTByYVg==
+  dependencies:
+    tslib "^1.9.0"
+
 [email protected], safe-buffer@~5.1.0, safe-buffer@~5.1.1:
   version "5.1.2"
   resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.2.tgz#991ec69d296e0313747d59bdfd2b745c35f8828d"