Bump poetry from 1.1.6 to 1.1.9 in /.github (#115)

Bumps [poetry](https://github.com/python-poetry/poetry) from 1.1.6 to 1.1.9.
- [Release notes](https://github.com/python-poetry/poetry/releases)
- [Changelog](https://github.com/python-poetry/poetry/blob/master/CHANGELOG.md)
- [Commits](python-poetry/poetry@1.1.6...1.1.9)

---
updated-dependencies:
- dependency-name: poetry
  dependency-type: direct:production
...

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

.github/requirements.txt

@@ -1,4 +1,4 @@
-poetry==1.1.6
+poetry==1.1.9
 tox>=3.23.1
 tox-poetry==0.4.0
 tox-docker==3.0.0