Stop installing Python 2.x

Fix #NONE

Author: Minggang Wang

.circleci/config.yml

@@ -20,7 +20,6 @@ jobs:
     - run: brew update
     - run: brew uninstall python
     - run: brew install python
-    - run: brew install python@2
     - run: brew install wget cmake cppcheck tinyxml eigen pcre poco
     - run: brew install openssl
     - run: brew install asio