Bump rxjs from 7.5.6 to 7.8.1

Bumps [rxjs](https://github.com/reactivex/rxjs) from 7.5.6 to 7.8.1.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/7.8.1/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@7.5.6...7.8.1)

---
updated-dependencies:
- dependency-name: rxjs
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -107,7 +107,7 @@
     "ng2-charts": "4.0.0",
     "ngx-infinite-scroll": "14.0.0",
     "ngx-webstorage": "10.0.1",
-    "rxjs": "7.5.6",
+    "rxjs": "7.8.1",
     "tslib": "2.5.2",
     "zone.js": "0.11.6"
   },