chore(deps): bump flake8-import-order from 0.12 to 0.18.2

Bumps [flake8-import-order](https://github.com/PyCQA/flake8-import-order) from 0.12 to 0.18.2.
- [Changelog](https://github.com/PyCQA/flake8-import-order/blob/master/CHANGELOG.rst)
- [Commits](PyCQA/flake8-import-order@0.12...0.18.2)

---
updated-dependencies:
- dependency-name: flake8-import-order
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

test-requirements.txt

@@ -1,2 +1,2 @@
-flake8-import-order==0.12 # LGPLv3
+flake8-import-order==0.18.2 # LGPLv3
 stestr>=1.0.0 # Apache-2.0