Bump cross-fetch from 2.2.3 to 2.2.6 in /staker-rewards

Bumps [cross-fetch](https://github.com/lquixada/cross-fetch) from 2.2.3 to 2.2.6.
- [Release notes](https://github.com/lquixada/cross-fetch/releases)
- [Commits](lquixada/cross-fetch@v2.2.3...v2.2.6)

---
updated-dependencies:
- dependency-name: cross-fetch
  dependency-type: indirect
...

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

Author: dependabot[bot]