Bump pymediawiki from 0.7.2 to 0.7.3 in /bodhi-server

Bumps [pymediawiki](https://github.com/barrust/mediawiki) from 0.7.2 to 0.7.3.
- [Release notes](https://github.com/barrust/mediawiki/releases)
- [Changelog](https://github.com/barrust/mediawiki/blob/master/CHANGELOG.md)
- [Commits](barrust/mediawiki@v0.7.2...v0.7.3)

---
updated-dependencies:
- dependency-name: pymediawiki
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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