Bump rxjs from 6.6.7 to 7.8.1

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.6.7 to 7.8.1.
- [Changelog](https://github.com/ReactiveX/rxjs/blob/7.8.1/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.6.7...7.8.1)

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

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

package.json

@@ -26,7 +26,7 @@
     "crypto-js": "^4.0.0",
     "http-link-header": "^1.0.2",
     "node-fetch": "^2.6.0",
-    "rxjs": "^6.5.4",
+    "rxjs": "^7.8.1",
     "valid-url": "^1.0.9"
   },
   "devDependencies": {