www/youtube_dl: update to 2021.03.31

Changes:	https://github.com/ytdl-org/youtube-dl/releases/tag/2021.03.31
Reported by:	GitHub (watch releases)

www/youtube_dl/Makefile

 # $FreeBSD$
 
 PORTNAME=	youtube_dl
-PORTVERSION=	2021.03.25
+PORTVERSION=	2021.03.31
 CATEGORIES=	www
 MASTER_SITES=	https://yt-dl.org/downloads/${PORTVERSION}/
 DISTNAME=	youtube-dl-${PORTVERSION}

www/youtube_dl/distinfo

-TIMESTAMP = 1616605429
-SHA256 (youtube-dl-2021.03.25.tar.gz) = a303cfd327938e3f15890099be79958cc17d536d1f985301d5462e487af3485f
-SIZE (youtube-dl-2021.03.25.tar.gz) = 3313712
+TIMESTAMP = 1616605588
+SHA256 (youtube-dl-2021.03.31.tar.gz) = f215d0e297febca0552e309dba12d62c53a56ed138de314d63b7fb80617e6ceb
+SIZE (youtube-dl-2021.03.31.tar.gz) = 3315008