dhcp-relay from network:dhcp project

对于 openSUSE Tumbleweed，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/openSUSE_Tumbleweed/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 openSUSE Factory ARM，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/openSUSE_Factory_ARM/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 openSUSE 13.1，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/openSUSE_13.1/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 15.4，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/15.4/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 15.3，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/15.3/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 SLE 12 SP5，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/SLE_12_SP5/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 SLE 11 SP2，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/SLE_11_SP2/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 SLE 11 SP1，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/SLE_11_SP1/network:dhcp.repo
zypper refresh
zypper install dhcp-relay

对于 SLE 11，请以根用户 root 运行下面命令：

zypper addrepo https://download.opensuse.org/repositories/network:dhcp/SLE_11/network:dhcp.repo
zypper refresh
zypper install dhcp-relay