build(deps-dev): bump rxjs from 6.6.3 to 6.6.6

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-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

yarn.lock

@@ -5746,9 +5746,9 @@ rxjs-compat@^6.5.4:
   integrity sha512-y+wUqq7bS2dG+7rH2fNMoxsDiJ32RQzFxZQE/JdtpnmEZmwLQrb1tCiItyHxdXJHXjmHnnzFscn3b6PEmORGKw==
 
 rxjs@^6.5.0, rxjs@^6.5.4:
-  version "6.6.3"
-  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.3.tgz#8ca84635c4daa900c0d3967a6ee7ac60271ee552"
-  integrity sha512-trsQc+xYYXZ3urjOiJOuCOa5N3jAZ3eiSpQB5hIT8zGlL2QfnHLJ2r7GMkBGuIausdJN1OneaI6gQlsqNHHmZQ==
+  version "6.6.6"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.6.tgz#14d8417aa5a07c5e633995b525e1e3c0dec03b70"
+  integrity sha512-/oTwee4N4iWzAMAL9xdGKjkEHmIwupR3oXbQjCKywF1BeFohswF3vZdogbmEF6pZkOsXTzWkrZszrWpQTByYVg==
   dependencies:
     tslib "^1.9.0"