Add linux-tgz release file

[mac-zhou]

add a linx tgz(tar.gz) release file that can use by Ansible Unarchive
ansible-playbook like:

  - name: Download & Unarchive go-shadowsocks2
    unarchive:
      remote_src: yes
      src: https://github.com/shadowsocks/go-shadowsocks2/releases/download/{{ version }}/shadowsocks2-linux.tgz
      dest: /usr/bin

  - name: Copy & Add go-shadowsocks2 systemd  service
    copy:
      src: go-shadowsocks2.service
      dest: /lib/systemd/system/go-shadowsocks2.service

  - name: Start & Enable go-shadowsocks2 service
    systemd:
      name: go-shadowsocks2
      state: started
      enabled: yes
      daemon_reload: yes

file go-shadowsocks2.service like:

[Unit]
Description=Shadowsocks2
Wants=network-online.target
After=network-online.target

[Service]
User=nobody
PermissionsStartOnly=true
ExecStart=/usr/bin/shadowsocks2-linux -s 'ss://AEAD_CHACHA20_POLY1305:1234@:5678'
Nice=-10
KillMode=process
Restart=on-failure
ProtectSystem=full
ProtectHome=true
PrivateTmp=true
PrivateDevices=true
NoNewPrivileges=true

[Install]
WantedBy=multi-user.target%