Merge branch 'master' into fix-style

Author: montyly

.github/workflows/ci.yml

@@ -27,8 +27,9 @@ jobs:
           python-version: 3.8
       - name: Install dependencies
         run: |
-          sudo wget -O /usr/bin/solc https://github.com/ethereum/solidity/releases/download/v0.5.11/solc-static-linux
-          sudo chmod +x /usr/bin/solc
+          pip install solc-select
+          solc-select install 0.5.11
+          solc-select use 0.5.11
       - name: Run Tests
         env:
           TEST_TYPE: ${{ matrix.type }}

program-analysis/echidna/exercises/exercise1/solution.sol

@@ -1,5 +1,7 @@
-// SPDX-License-Identifier: GPL-3.0
-pragma solidity ^0.5.0;
+//SPDX-License-Identifier: AGPL-3.0-or-later
+pragma solidity <0.8.0;
+
+import "token.sol";
 
 import "./token.sol";
 

program-analysis/echidna/exercises/exercise1/template.sol

@@ -1,5 +1,7 @@
-// SPDX-License-Identifier: GPL-3.0
-pragma solidity ^0.5.0;
+//SPDX-License-Identifier: AGPL-3.0-or-later
+pragma solidity <0.8.0;
+
+import "token.sol";
 
 import "./token.sol";
 

program-analysis/echidna/exercises/exercise1/token.sol

@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: GPL-3.0
-pragma solidity ^0.5.0;
+//SPDX-License-Identifier: AGPL-3.0-or-later
+pragma solidity <0.8.0;
 
 contract Ownable {
     address public owner = msg.sender;