ci(travis): remove brew tap

Author: felixfbecker

.travis.yml

@@ -30,7 +30,6 @@ jobs:
       before_install:
         # Fix ruby error https://github.com/Homebrew/brew/issues/3299
         - brew update
-        - brew tap homebrew/homebrew-php
         - brew install php@7.1
         - brew link --force --overwrite php@7.1
         - pecl install xdebug-2.6.0