databases/rubygem-redis: Update to 4.8.0

Changes:	https://github.com/redis/redis-rb/blob/master/CHANGELOG.md

databases/rubygem-redis/Makefile

 PORTNAME=	redis
-PORTVERSION=	4.7.1
+PORTVERSION=	4.8.0
 CATEGORIES=	databases rubygems
 MASTER_SITES=	RG
 

databases/rubygem-redis/distinfo

-TIMESTAMP = 1657199049
-SHA256 (rubygem/redis-4.7.1.gem) = ecb256d4e53ead3eca05bf394dd100e6a162c136f461fe752ddf5d35b64a2df6
-SIZE (rubygem/redis-4.7.1.gem) = 68608
+TIMESTAMP = 1661599375
+SHA256 (rubygem/redis-4.8.0.gem) = 2000cf5014669c9dc821704b6d322a35a9a33852a95208911d9175d63b448a44
+SIZE (rubygem/redis-4.8.0.gem) = 69120