fix: aggregator interface (#129)

* fix: aggregator interface with soften version

* fix: abi encoder

* fix: AaveV3 import

src/AaveGovernanceV2.sol

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 pragma solidity >=0.6.0;
-pragma abicoder v2;
+pragma experimental ABIEncoderV2;
 
 interface IGovernanceStrategy {
   /**

src/AaveV2.sol

@@ -2,7 +2,7 @@
 pragma solidity >=0.6.0;
 pragma experimental ABIEncoderV2;
 
-import {AggregatorInterface} from 'aave-v3-core/contracts/dependencies/chainlink/AggregatorInterface.sol';
+import {AggregatorInterface} from './common/AggregatorInterface.sol';
 
 library DataTypes {
   // refer to the whitepaper, section 1.1 basic concepts for a formal description of these properties.

src/common/AggregatorInterface.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.6.0;
+
+interface AggregatorInterface {
+  function latestAnswer() external view returns (int256);
+
+  function latestTimestamp() external view returns (uint256);
+
+  function latestRound() external view returns (uint256);
+
+  function getAnswer(uint256 roundId) external view returns (int256);
+
+  function getTimestamp(uint256 roundId) external view returns (uint256);
+
+  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
+
+  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
+}