feat: stake account type in anchor

[f8122dac91]

references:

• https://github.com/project-serum/anchor/blob/master/spl/src
• https://github.com/marinade-finance/liquid-staking-program/blob/a309057f1eb3413070846d34e8fd5d83e99dc1c6/programs/marinade-finance/src/stake_wrapper.rs

[f8122dac91]

Resolved on the fork of the anchor repo: https://github.com/igneous-labs/anchor The new anchor dependencies were added here: https://github.com/igneous-labs/unstake/pull/11/commits/754a61920ddd8bcabe9cfe78b512db9aa8498801