dev-env: Fix syntax
Our CI environment uses Python 2 which doesn't support f-strings. We
should update to Python 3 but in the meantime we need a working CI.
@@ -173,7 +173,7 @@ def validate_kind_version():
delta = semver.compare(actual_version, min_version)
if delta < 0:
- raise Exit(message=f"kind version >= {min_version} required")
+ raise Exit(message="kind version >= {} required".format(min_version))
@task(help={
