add uniV3RouteAdapter

contracts/SmartRoute/intf/IUniV3.sol

@@ -0,0 +1,12 @@
+pragma solidity 0.6.9;
+pragma experimental ABIEncoderV2;
+
+interface IUniV3 {
+    function swap(
+        address recipient,
+        bool zeroForOne,
+        int256 amountSpecified,
+        uint160 sqrtPriceLimitX96,
+        bytes calldata data
+    ) external returns (int256 amount0, int256 amount1);
+}