Custom template tag keyword only arguments

[Alexander Allakhverdiyev]

Example tag with a keyword-only argument

@register.simple_tag(takes_context=True)
def my_tag(context, arg1, *, kwarg2='n/a'):
    return ''

Html code

<div>bla bla bla</div>
{% my_tag 'arg_1_value' kwarg_2='kwarg_value' %}

Result

ValueError: Function has keyword-only arguments or annotations, use getfullargspec() API which can support them

Proposed solution: use getfullargspec instead of getargspec in templates/base.py