kali 更换更新源

（其实系统本身就自带了更新源，去掉其注释也是可以的，现在官方源的下载速度也还ok，下面的三选一亦可）
  #kali官方源
    deb http://http.kali.org/kali kali-rolling main non-free contrib
    #中科大的源
    deb http://mirrors.ustc.edu.cn/kali kali-rolling main non-free contrib
    deb http://mirrors.ustc.edu.cn/kali kali-rolling main contrib non-free
    deb-src http://mirrors.ustc.edu.cn/kali kali-rolling main contrib non-free
    deb http://mirrors.ustc.edu.cn/kali-security kali-current/updates main contrib non-free
    deb-src http://mirrors.ustc.edu.cn/kali-security kali-current/updates main contrib non-free
    #阿里云源
    deb http://mirrors.aliyun.com/kali kali-rolling main non-free contrib
    deb http://mirrors.aliyun.com/kali-security/ kali-rolling main contrib non-free
    deb-src http://mirrors.aliyun.com/kali-security/ kali-rolling main contrib non-free
   #阿里云 
deb http://mirrors.aliyun.com/kali kali-rolling main non-free contrib deb-src http://mirrors.aliyun.com/kali kali-rolling main non-free contrib
 #清华大学
 deb http://mirrors.tuna.tsinghua.edu.cn/kali kali-rolling main contrib non-free deb-src https://mirrors.tuna.tsinghua.edu.cn/kali kali-rolling main contrib non-free 
#浙大
 deb http://mirrors.zju.edu.cn/kali kali-rolling main contrib non-free deb-src http://mirrors.zju.edu.cn/kali kali-rolling main contrib non-free 
#东软大学
 deb http://mirrors.neusoft.edu.cn/kali kali-rolling/main non-free contrib deb-src http://mirrors.neusoft.edu.cn/kali kali-rolling/main non-free contrib