Bump semver in /example/federation/integration/gateway (#621)

Bumps [semver](https://github.com/npm/node-semver) from 7.3.8 to 7.5.4.
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/main/CHANGELOG.md)
- [Commits](npm/node-semver@v7.3.8...v7.5.4)

---
updated-dependencies:
- dependency-name: semver
  dependency-type: indirect
...

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