`get_associated_token_address` helper method shoule be retired

[icy-comet]

This helper function silently uses the hardcoded classic token program's ID. This can trip up the users.

associated-token-account/interface/src/address.rs

Line 34 in 109de0b

&inline_spl_token::ID,

[joncinque]

Good point, we can start by marking the function as deprecated