PHP 5.6 and 7.0 doesn't run on Catalina - openssl 1.0.0 needed
php@5.6 php@7.0 被brew官方移除
### 安装方式
```bash
brew tap exolnet/homebrew-deprecated
brew install exolnet/deprecated/php@5.6
```
### 出现报错
```bash
dyld: Library not loaded: /usr/local/opt/openssl/lib/