mail/mailslurper: fix build on riscv64

Bump golang.org/x/sys dependency to a version new enough
to support riscv64-freebsd.

Sponsored by:	Berliner Linux User Group e.V.
Approved by:	portmgr (build fix blanket)

mail/mailslurper/Makefile

 PORTNAME=	mailslurper
 PORTVERSION=	1.14.2.g20201217
-PORTREVISION=	2
+PORTREVISION=	3
 CATEGORIES=	mail
 
 MAINTAINER=	einar@isnic.is
@@ -24,7 +24,7 @@ GH_TUPLE=	\
 		golang-sql:civil:cb61b32ac6fe:golang_sql_civil/vendor/github.com/golang-sql/civil \
 		golang:crypto:2aa609cf4a9d:golang_crypto/vendor/golang.org/x/crypto \
 		golang:net:0de0cce0169b:golang_net/vendor/golang.org/x/net \
-		golang:sys:04cbcbbfeed8:golang_sys/vendor/golang.org/x/sys \
+		golang:sys:v0.6.0:golang_sys/vendor/golang.org/x/sys \
 		golang:text:v0.3.2:golang_text/vendor/golang.org/x/text \
 		gorilla:context:v1.1.1:gorilla_context/vendor/github.com/gorilla/context \
 		gorilla:securecookie:v1.1.1:gorilla_securecookie/vendor/github.com/gorilla/securecookie \

mail/mailslurper/distinfo

-TIMESTAMP = 1676035680
+TIMESTAMP = 1679317165
 SHA256 (mailslurper-mailslurper-1.14.2.g20201217-3231e9f9_GH0.tar.gz) = 7102870081e73b85252b5a6e9559397646f3af0316d3bb3eb4a6bdb83d06cb6c
 SIZE (mailslurper-mailslurper-1.14.2.g20201217-3231e9f9_GH0.tar.gz) = 2545305
 SHA256 (adampresley-webframework-0c93acb6716f_GH0.tar.gz) = 5d145f9dc678351f55420443b47c67097619a52dab87f4ae41963d6c412e6a25
@@ -15,8 +15,8 @@ SHA256 (golang-crypto-2aa609cf4a9d_GH0.tar.gz) = 5fe90bd9def2114d4772a2e394ac1a5
 SIZE (golang-crypto-2aa609cf4a9d_GH0.tar.gz) = 1726702
 SHA256 (golang-net-0de0cce0169b_GH0.tar.gz) = 74c2cbbb7d9fbbb024dea88d3003939d5e394f0e01dbbf8c431fd90a82f1cd56
 SIZE (golang-net-0de0cce0169b_GH0.tar.gz) = 1172526
-SHA256 (golang-sys-04cbcbbfeed8_GH0.tar.gz) = 8f194ecf5ac4834ba7e3543f38f67a8972ede9fee67e2142eb72644213335824
-SIZE (golang-sys-04cbcbbfeed8_GH0.tar.gz) = 1535773
+SHA256 (golang-sys-v0.6.0_GH0.tar.gz) = b4f6d17c7a128f76169964b437cb66b3f2dbf9a33361928ec19dfecf7b03fc54
+SIZE (golang-sys-v0.6.0_GH0.tar.gz) = 1434234
 SHA256 (golang-text-v0.3.2_GH0.tar.gz) = 0b9309698f5708531c5377ab1e29b423a6d9e20c55a8d386c3b8283428212f22
 SIZE (golang-text-v0.3.2_GH0.tar.gz) = 7168069
 SHA256 (gorilla-context-v1.1.1_GH0.tar.gz) = 2dfdd051c238695bf9ebfed0bf6a8c533507ac0893bce23be5930e973736bb03