Use with for file usage
Use with for file usage

Replace old style file open and close with a `with` block for clarity
and it's error handling.

denisbalyko/django-wkhtmltopdf,unrealsolver/django-wkhtmltopdf,fankcoder/django-wkhtmltopdf,powderflask/django-wkhtmltopdf,halfnibble/django-wkhtmltopdf,incuna/django-wkhtmltopdf,tclancy/django-wkhtmltopdf,incuna/django-wkhtmltopdf,unrealsolver/django-wkhtmltopdf,fankcoder/django-wkhtmltopdf,powderflask/django-wkhtmltopdf,halfnibble/django-wkhtmltopdf,denisbalyko/django-wkhtmltopdf,tclancy/django-wkhtmltopdf