[audit]#1 add decimals and name to lptoken

contracts/intf/IERC20.sol

@@ -4,7 +4,6 @@
 pragma solidity 0.6.9;
 pragma experimental ABIEncoderV2;
 
-
 /**
  * @dev Interface of the ERC20 standard as defined in the EIP.
  */
@@ -14,6 +13,10 @@ interface IERC20 {
      */
     function totalSupply() external view returns (uint256);
 
+    function decimals() external view returns (uint8);
+
+    function name() external view returns (string memory);
+
     /**
      * @dev Returns the amount of tokens owned by `account`.
      */