devel/py-nbclassic: Update to 0.3.0

Changes:	https://github.com/jupyterlab/nbclassic/releases

devel/py-nbclassic/Makefile

 # Created by: Po-Chuan Hsieh <sunpoet@FreeBSD.org>
 
 PORTNAME=	nbclassic
-PORTVERSION=	0.2.8
+PORTVERSION=	0.3.0
 CATEGORIES=	devel python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}

devel/py-nbclassic/distinfo

-TIMESTAMP = 1620928607
-SHA256 (nbclassic-0.2.8.tar.gz) = 9553dcd9ae4d932db640dad0daa186fe6c64e69ec2159868c0b38d7adef9b3b5
-SIZE (nbclassic-0.2.8.tar.gz) = 21862
+TIMESTAMP = 1621699719
+SHA256 (nbclassic-0.3.0.tar.gz) = d8c1cb1f767ada80f02407f2607bbd21eb7bf44f4be125e8dd299facf58ce94d
+SIZE (nbclassic-0.3.0.tar.gz) = 22120