[DOCS] Change >=0.7.0 to ^0.7.0

docs/common-patterns.rst

@@ -28,7 +28,7 @@ you receive the funds of the person who is now the richest.
 ::
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >=0.7.0;
+    pragma solidity ^0.7.0;
 
     contract WithdrawalContract {
         address public richest;
@@ -62,7 +62,7 @@ This is as opposed to the more intuitive sending pattern:
 ::
 
     // SPDX-License-Identifier: GPL-3.0
-    pragma solidity >=0.7.0;
+    pragma solidity ^0.7.0;
 
     contract SendContract {
         address payable public richest;