devel/rubygem-oj: Update to 3.13.15

Changes:	https://github.com/ohler55/oj/blob/develop/CHANGELOG.md

devel/rubygem-oj/Makefile

 # Created by: Steve Wills <swills@FreeBSD.org>
 
 PORTNAME=	oj
-PORTVERSION=	3.13.14
+PORTVERSION=	3.13.15
 CATEGORIES=	devel rubygems
 MASTER_SITES=	RG
 

devel/rubygem-oj/distinfo

-TIMESTAMP = 1654275943
-SHA256 (rubygem/oj-3.13.14.gem) = 18a15d45192ff305e11f804caf075338bfffc73a5be08d80896b753c37b36b2d
-SIZE (rubygem/oj-3.13.14.gem) = 264192
+TIMESTAMP = 1657199087
+SHA256 (rubygem/oj-3.13.15.gem) = 914a4acd93e14955d67bef600680b62b952affa03d9899d811850b9dab80a7b1
+SIZE (rubygem/oj-3.13.15.gem) = 265216