Update README.md (coolsnowwolf#5174)

编译提示/bin/sh: 1: rsync: not found
增加 rsync 默认依赖

README.md

@@ -16,7 +16,7 @@ Welcome to Lean's  git source of OpenWrt and packages
 
 2. 命令行输入 `sudo apt-get update` ，然后输入
 `
-sudo apt-get -y install build-essential asciidoc binutils bzip2 gawk gettext git libncurses5-dev libz-dev patch python3.5 python2.7 unzip zlib1g-dev lib32gcc1 libc6-dev-i386 subversion flex uglifyjs git-core gcc-multilib p7zip p7zip-full msmtp libssl-dev texinfo libglib2.0-dev xmlto qemu-utils upx libelf-dev autoconf automake libtool autopoint device-tree-compiler g++-multilib antlr3 gperf wget swig
+sudo apt-get -y install build-essential asciidoc binutils bzip2 gawk gettext git libncurses5-dev libz-dev patch python3.5 python2.7 unzip zlib1g-dev lib32gcc1 libc6-dev-i386 subversion flex uglifyjs git-core gcc-multilib p7zip p7zip-full msmtp libssl-dev texinfo libglib2.0-dev xmlto qemu-utils upx libelf-dev autoconf automake libtool autopoint device-tree-compiler g++-multilib antlr3 gperf wget swig rsync
 `
 
 3. 使用 `git clone https://github.com/coolsnowwolf/lede` 命令下载好源代码，然后 `cd lede` 进入目录