Check for uses of old % formatting rather than .format() method
copied from cf-staging / flake8-pep3101conda install conda-forge::flake8-pep3101
conda install conda-forge/label/cf201901::flake8-pep3101
conda install conda-forge/label/cf202003::flake8-pep3101
conda install conda-forge/label/gcc7::flake8-pep3101