Problem 1

    - Root composer.json requires wechatpay/wechatpay 1.3 -> satisfiable by wechatpay/wechatpay[1.3.0].

    - wechatpay/wechatpay 1.3.0 requires php >=7.2 -> your php version (7.0.29) does not satisfy that requirement.

目前看要升级公私钥验签php的版本最低是7.2，7.0怎么兼容