Fix tests by adding dependency constraint (#528)

Author: llucax

pyproject.toml

@@ -110,6 +110,9 @@ dev-pytest = [
   "cookiecutter == 2.6.0", # For checking the cookiecutter scripts
   "jinja2 == 3.1.6", # For checking the cookiecutter scripts
   "sybil >= 6.1.1, < 10", # Should be consistent with the extra-lint-examples dependency
+  # This is a hack to overcome an outdated version check in requests, see
+  # https://github.com/frequenz-floss/frequenz-repo-config-python/issues/527
+  "chardet < 6",
 ]
 dev = [
   "frequenz-repo-config[dev-mkdocs,dev-flake8,dev-formatting,dev-mkdocs,dev-mypy,dev-noxfile,dev-pylint,dev-pytest]",