Missing Allocator.sol interface

Author: Filip-L

src/interfaces/IAllocator.sol

@@ -70,6 +70,17 @@ interface IAllocator {
      */
     function addAllowance(address allocator, uint256 amount) external;
 
+    /**
+     * @notice Decrease Allocator allowance
+     * @dev This function can only be called by the owner
+     * @param allocator Allocator whose allowance is reduced
+     * @param amount Amount to decrease the allowance
+     * @dev Emits AllowanceChanged event
+     * @dev Reverts if trying to decrease allowance by 0
+     * @dev Reverts if allocator allowance is already 0
+     */
+    function decreaseAllowance(address allocator, uint256 amount) external;
+
     /**
      * @notice Set allowance of an Allocator. Can be used to remove allowance.
      * @param allocator Allocator