TOOL-13593 Use "openzfs" instead of "zfsonlinux" for upstream URL (#231)

The "zfsonlinux" GitHub project was moved to "openzfs" a while back, so
we should reflect that in our upstream URL for the ZFS package. It seems
like the old URL still works, and automatically redirects to the new
URL, so this isn't strictly required.

Author: Prakash Surya

packages/zfs/config.sh

@@ -19,7 +19,7 @@
 DEFAULT_PACKAGE_GIT_URL="https://github.com/delphix/zfs.git"
 PACKAGE_DEPENDENCIES="@linux-kernel delphix-rust"
 
-UPSTREAM_GIT_URL="https://github.com/zfsonlinux/zfs.git"
+UPSTREAM_GIT_URL="https://github.com/openzfs/zfs.git"
 UPSTREAM_GIT_BRANCH="master"
 
 function prepare() {