Fixed a mistake in the fee calculation with round up

Author: Sean329

patterns/flash-loans/README.md

@@ -76,7 +76,7 @@ function flashLoan(
     uint256 balanceBefore = token.balanceOf(address(this));
     require(balanceBefore >= borrowAmount, 'too much');
     // Compute the fee, rounded up.
-    uint256 fee = FEE_BPS * (borrowAmount + 1e4-1) / 1e4;
+    uint256 fee = (FEE_BPS * borrowAmount + 1e4-1) / 1e4;
     // Transfer tokens to the borrower contract.
     token.transfer(address(borrower), borrowAmount);
     // Let the borrower do its thing.