make some fixes for macos

dot_gitconfig.tmpl

@@ -1,9 +1,9 @@
 [credential "https://github.com"]
 	helper = 
-	helper = !~/.webman/bin/gh auth git-credential
+	helper = !gh auth git-credential
 [credential "https://gist.github.com"]
 	helper = 
-	helper = !~/.webman/bin/gh auth git-credential
+	helper = !gh auth git-credential
 
 [user]
 	email = {{ .email | quote }}

run_once_before_install.sh.tmpl

@@ -31,6 +31,8 @@ echo "macOS detected"
 
 if test -x /usr/local/bin/brew; then
   echo "Homebrew already installed"
+elif test -x /opt/homebrew/bin/brew; then
+  echo "Homebrew already installed"
 else
   echo "\n[-] Installing Homebrew [-]"
   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"