net-im/zkgroup: Revert update to 0.8.2

This version of zkgroup is too new for net-im/signal-cli 0.9.0. Roll
back. A roll-back of net-im/signal-cli will follow.

This reverts commit f7ffe77.

net-im/zkgroup/Makefile

@@ -1,6 +1,7 @@
 PORTNAME=	zkgroup
 DISTVERSIONPREFIX=	v
-DISTVERSION=	0.8.2
+DISTVERSION=	0.7.4
+PORTEPOCH=	1
 CATEGORIES=	net-im
 
 MAINTAINER=	0mp@FreeBSD.org

net-im/zkgroup/distinfo

@@ -1,4 +1,4 @@
-TIMESTAMP = 1634799333
+TIMESTAMP = 1633413767
 SHA256 (rust/crates/aead-0.4.1.crate) = 922b33332f54fc0ad13fa3e514601e8d30fb54e1f3eadc36643f6526db645621
 SIZE (rust/crates/aead-0.4.1.crate) = 14606
 SHA256 (rust/crates/aes-0.7.4.crate) = 495ee669413bfbe9e8cace80f4d3d78e6d8c8d99579f97fb93bde351b185f2d4
@@ -219,8 +219,8 @@ SHA256 (rust/crates/winapi-x86_64-pc-windows-gnu-0.4.0.crate) = 712e227841d057c1
 SIZE (rust/crates/winapi-x86_64-pc-windows-gnu-0.4.0.crate) = 2947998
 SHA256 (rust/crates/zeroize-1.3.0.crate) = 4756f7db3f7b5574938c3eb1c117038b8e07f95ee6718c0efad4ac21508f1efd
 SIZE (rust/crates/zeroize-1.3.0.crate) = 15913
-SHA256 (signalapp-zkgroup-v0.8.2_GH0.tar.gz) = c2f758cb96c4e49b18439c8c0ae06d129a8f46549b63a9498cf54d7d64489dcc
-SIZE (signalapp-zkgroup-v0.8.2_GH0.tar.gz) = 281950
+SHA256 (signalapp-zkgroup-v0.7.4_GH0.tar.gz) = b0fdf42c35ea08dec063b903967bef2a461ac1717dc38ee0b8757557b07cb204
+SIZE (signalapp-zkgroup-v0.7.4_GH0.tar.gz) = 253752
 SHA256 (signalapp-curve25519-dalek-477356e017c7cc2aa168f956786b34690870768f_GH0.tar.gz) = df72210a25f199e6da980c0ee13bd5cfdcfcea6f203a8ac3cb7c9f3c9c0a5511
 SIZE (signalapp-curve25519-dalek-477356e017c7cc2aa168f956786b34690870768f_GH0.tar.gz) = 517253
 SHA256 (signalapp-poksho-8bb8c61c18e7bbe93c094ed91be52b9f96c1c5cd_GH0.tar.gz) = 855836c2ce16053091e1ab022d0ce53914f25167e7b1256a81205ff549658074