Bump poetry from 1.1.4 to 1.1.5 in /.github/workflows

Bumps [poetry](https://github.com/python-poetry/poetry) from 1.1.4 to 1.1.5.
- [Release notes](https://github.com/python-poetry/poetry/releases)
- [Changelog](https://github.com/python-poetry/poetry/blob/1.1.5/CHANGELOG.md)
- [Commits](python-poetry/poetry@1.1.4...1.1.5)

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

Author: dependabot[bot]

.github/workflows/constraints.txt

@@ -1,5 +1,5 @@
 pip==20.2.4
 nox==2020.8.22
 nox-poetry==0.8.3
-poetry==1.1.4
+poetry==1.1.5
 virtualenv==20.1.0