Bump rxjs from 6.6.7 to 7.5.4

Bumps [rxjs](https://github.com/reactivex/rxjs) from 6.6.7 to 7.5.4.
- [Release notes](https://github.com/reactivex/rxjs/releases)
- [Changelog](https://github.com/ReactiveX/rxjs/blob/master/CHANGELOG.md)
- [Commits](ReactiveX/rxjs@6.6.7...7.5.4)

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

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

package.json

@@ -58,7 +58,7 @@
     "ngx-countup": "^13.0.0",
     "ngx-file-drop": "^13.0.0",
     "ngx-pagination": "^5.1.1",
-    "rxjs": "^6.6.7",
+    "rxjs": "^7.5.4",
     "swagger-ui": "^4.5.2",
     "tslib": "^2.3.1",
     "zone.js": "~0.11.5"