Bump nox-poetry from 0.7.1 to 0.8.1 in /.github/workflows

Bumps [nox-poetry](https://github.com/cjolowicz/nox-poetry) from 0.7.1 to 0.8.1.
- [Release notes](https://github.com/cjolowicz/nox-poetry/releases)
- [Commits](cjolowicz/nox-poetry@v0.7.1...v0.8.1)

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

.github/workflows/constraints.txt

@@ -1,5 +1,5 @@
 pip==21.0.1
 nox==2020.12.31
-nox-poetry==0.7.1
+nox-poetry==0.8.1
 poetry==1.0.10
 virtualenv==20.4.2