updated token-program.md course

[Ozodimgba]

Problem

Some of the methods used in the @solana/spl-token package in this course have been updated and might cause confusion for learners interacting with the package presently

Summary of Changes

• createMint now uses createInitializeMint2Instruction,
• createAssociatedTokenAccount method replaced asynchronous getAssociatedTokenAddress calls with synchronous getAssociatedTokenAddressSync to make sure token account is only created when none exists
• allowOwnerOffCurve parameter is a necessary parameter for certain use case like vaults and interactions with multi sig wallets. see the @solana/spl-token commit here