Audit found that the transferFrom function never deducts the allowance value

[michael7245]

https://github.com/jklepatch/eattheblocks/blob/e74971499c556759757ff1d96328082092644515/screencast/308-create-bep20-token-bsc/Token.sol#L30

Hello,

We used this code for our BEP-20 token project as none of us really had any smart contract experience. Our project ended up getting a lot of traction and so we took the next step and got an audit from Certik. They raised a critical error with the TransferFrom function because the allowance value never gets deducted.

Obviously we don't blame you because this contract was used for learning purposes but I wanted to let you know just in case you had thought about this before and felt there was another way this error was accounted for. Thanks!

[michael7245]

@jklepatch