devel/py-num2words: Added RUN_DEPENDS from devel/py-docopt

This additional dependency fixes a runtime error when
trying to show help:

    $ num2words --help
    Traceback (most recent call last):
      File "/usr/local/bin/num2words", line 55, in <module>
        from docopt import docopt
    ModuleNotFoundError: No module named 'docopt'

devel/py-num2words/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	num2words
 PORTVERSION=	0.5.13
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	devel python
 MASTER_SITES=	PYPI
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
@@ -11,6 +11,8 @@ WWW=		https://github.com/savoirfairelinux/num2words
 
 LICENSE=	LGPL21
 
+RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}docopt>=0.6.0:devel/py-docopt@${PY_FLAVOR}
+
 USES=		python
 USE_PYTHON=	distutils autoplist