feat: add balancer v2 executor

foundry/lib/balancer-labs/v2-interfaces/contracts/liquidity-mining/IRewardsOnlyGauge.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+pragma solidity >=0.7.0 <0.9.0;
+
+import "./IChildChainStreamer.sol";
+import "./IRewardTokenDistributor.sol";
+
+// For compatibility, we're keeping the same function names as in the original Curve code, including the mixed-case
+// naming convention.
+// solhint-disable func-name-mixedcase
+
+interface IRewardsOnlyGauge is IRewardTokenDistributor {
+    function initialize(
+        address pool,
+        address streamer,
+        bytes32 claimSignature
+    ) external;
+
+    // solhint-disable-next-line func-name-mixedcase
+    function lp_token() external view returns (IERC20);
+
+    function reward_contract() external view returns (IChildChainStreamer);
+
+    function set_rewards(
+        address childChainStreamer,
+        bytes32 claimSig,
+        address[8] calldata rewardTokens
+    ) external;
+
+    function last_claim() external view returns (uint256);
+}