statechannels: bump nitro and remove version change in build script

Author: abarmat

contracts/statechannels/GRTAssetHolder.sol

@@ -1,6 +1,9 @@
-pragma solidity ^0.6.12;
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.7.3;
 pragma experimental ABIEncoderV2;
 
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@statechannels/nitro-protocol/contracts/ERC20AssetHolder.sol";
 
 import "../governance/IController.sol";
@@ -14,9 +17,9 @@ contract GRTAssetHolder is ERC20AssetHolder {
 
     constructor(
         address _AdjudicatorAddress,
-        address _TokenAddress,
+        IERC20 _TokenAddress,
         IController _Controller
-    ) public ERC20AssetHolder(_AdjudicatorAddress, _TokenAddress) {
+    ) ERC20AssetHolder(_AdjudicatorAddress, _TokenAddress) {
         AdjudicatorAddress = _AdjudicatorAddress;
         Controller = _Controller;
     }

hardhat.config.ts

@@ -126,16 +126,7 @@ const config = {
   solidity: {
     compilers: [
       {
-        version: '0.7.3',
-        settings: {
-          optimizer: {
-            enabled: true,
-            runs: 200,
-          },
-        },
-      },
-      {
-        version: '0.6.12',
+        version: '0.7.4',
         settings: {
           optimizer: {
             enabled: true,

package-lock.json

@@ -23,7 +23,7 @@
     "@nomiclabs/hardhat-etherscan": "^2.0.0",
     "@nomiclabs/hardhat-waffle": "^2.0.0",
     "@openzeppelin/contracts": "^3.2.1-solc-0.7",
-    "@statechannels/nitro-protocol": "^0.7.1-next.534a803ee.74",
+    "@statechannels/nitro-protocol": "^0.11.2",
     "@tenderly/hardhat-tenderly": "^1.0.3",
     "@typechain/ethers-v5": "^1.0.0",
     "@types/bs58": "^4.0.1",

package.json

@@ -2,13 +2,5 @@
 
 set -eo pipefail
 
-# Allow these interfaces to be used from 0.6.x and 0.7.x contracts
-sed -i='' 's/pragma solidity ^0.7.0/pragma solidity >=0.6.0 <0.8.0/g' node_modules/@openzeppelin/contracts/math/SafeMath.sol
-sed -i='' 's/pragma solidity ^0.7.0/pragma solidity >=0.6.0 <0.8.0/g' node_modules/@openzeppelin/contracts/token/ERC20/IERC20.sol
-sed -i='' 's/pragma solidity ^0.7.0/pragma solidity >=0.6.0 <0.8.0/g' node_modules/@openzeppelin/contracts/cryptography/ECDSA.sol
-
-# Compile AttestationApp along with the rest of the contracts
-cp node_modules/@graphprotocol/statechannels/contracts/Attestation*.sol contracts/statechannels
-
 # Build
 npm run compile