Bump linode-api4 from 5.17.0 to 5.18.0 (#50)

Bumps [linode-api4](https://github.com/linode/linode_api4-python) from 5.17.0 to 5.18.0.
- [Release notes](https://github.com/linode/linode_api4-python/releases)
- [Commits](linode/linode_api4-python@v5.17.0...v5.18.0)

---
updated-dependencies:
- dependency-name: linode-api4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -1 +1 @@
-linode-api4==5.17.0
+linode-api4==5.18.0