Bump rxjs from 6.6.6 to 6.6.7 in /samples/lib/spa-angular-client

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.6.6 to 6.6.7.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/6.6.7/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.6.6...6.6.7)

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

Author: dependabot[bot]

samples/lib/spa-angular-client/package-lock.json

@@ -32,7 +32,7 @@
     "bootstrap": "^4.6.0",
     "bowser": "^2.11.0",
     "core-js": "^3.9.1",
-    "rxjs": "~6.6.6",
+    "rxjs": "~6.6.7",
     "tslib": "^2.1.0",
     "zone.js": "~0.10.2"
   },