build(deps): bump poetry from 1.4.2 to 1.5.0 in /devtools

Bumps [poetry](https://github.com/python-poetry/poetry) from 1.4.2 to 1.5.0.
- [Release notes](https://github.com/python-poetry/poetry/releases)
- [Changelog](https://github.com/python-poetry/poetry/blob/master/CHANGELOG.md)
- [Commits](python-poetry/poetry@1.4.2...1.5.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

devtools/requirements-poetry.in

@@ -1,3 +1,3 @@
 # Fixing this here as readthedocs can't use the compiled requirements-poetry.txt
 # due to conflicts.
-poetry==1.4.2
+poetry==1.5.0