chore: force tox environment to utf8

Windows defaults to cp1252 encoding which leads to an error during flake8 execution.

Signed-off-by: Peter Schuster <p.schuster@pilz.de>

Author: peschuster

tox.ini

@@ -27,6 +27,7 @@ commands_pre =
 commands =
     poetry run coverage run --source=cyclonedx -m unittest discover -t . -s tests -v
 setenv =
+    PYTHONUTF8=1
     PYTHONHASHSEED=0
     CDX_TEST_RECREATE_SNAPSHOTS={env:CDX_TEST_RECREATE_SNAPSHOTS:}