Book Store Smart Contract

Project Link:
https://github.com/emhaihsan/solidity-example/blob/main/BasicBookStore.sol
Functionality:
- Add a book with a title and price using the `addBook`.
- Update the price of a book using the `updateBookPrice`.
- Retrieve the price of a book using the `getBookPrice`.
- Check if a book is registered using the `isBookRegistered`.