增加vendor

vendor/github.com/go-pay/gopay/error.go

@@ -0,0 +1,16 @@
+package gopay
+
+import "errors"
+
+var (
+	MissWechatInitParamErr = errors.New("missing wechat init parameter")
+	MissAlipayInitParamErr = errors.New("missing alipay init parameter")
+	MissPayPalInitParamErr = errors.New("missing paypal init parameter")
+	MissParamErr           = errors.New("missing required parameter")
+	MarshalErr             = errors.New("marshal error")
+	UnmarshalErr           = errors.New("unmarshal error")
+	SignatureErr           = errors.New("signature error")
+	VerifySignatureErr     = errors.New("verify signature error")
+	CertNotMatchErr        = errors.New("cert not match error")
+	GetSignDataErr         = errors.New("get signature data error")
+)