upgrade tor package to v0.4.6.8-r0 (see below)

https://web.archive.org/web/20211219210312/https://gitweb.torproject.org/tor.git/plain/ChangeLog
https://git.alpinelinux.org/aports/commit/community/tor?h=3.15-stable&id=178008f6bd3a8c810e17902277ffa30bb59933a1

Dockerfile

@@ -1,7 +1,7 @@
 # https://pkgs.alpinelinux.org/packages?name=obfs4proxy&arch=x86_64
 FROM docker.io/alpine:3.15.0
 
-ARG TOR_PACKAGE_VERSION=0.4.6.7-r1
+ARG TOR_PACKAGE_VERSION=0.4.6.8-r0
 ARG OBFS4PROXY_PACKAGE_VERSION=0.0.11-r4
 RUN apk add --no-cache tor=$TOR_PACKAGE_VERSION \
     && apk add --no-cache obfs4proxy=$OBFS4PROXY_PACKAGE_VERSION \