spl-token: Add associated token account CreateIdempotent instruction

[thiagosantana-mb]

Very useful instruction to avoid burning fees on concurrent Token Account creation.
https://github.com/solana-labs/solana-program-library/blob/transfer-hook-interface-v0.8.2/associated-token-account/program/src/instruction.rs#L29

TX sample:
https://explorer.solana.com/tx/TNpMsmZ66UP2cePfvfhpNCXaevi2koYpqc6i9NXfTLf4ZMKBftprNh1q9N1iE3US1HR5FArzPHVFJWEcsmHwJCq?cluster=devnet

[michaelhly]

@thiagosantana-mb would you mind merging in the commit on master? I'm getting an error:

Error updating the branch: refusing to allow a Personal Access Token to create or update workflow .github/workflows/docs.yml without workflow scope

[thiagosantana-mb]

@thiagosantana-mb would you mind merging in the commit on master? I'm getting an error:

Error updating the branch: refusing to allow a Personal Access Token to create or update workflow .github/workflows/docs.yml without workflow scope

Sure, merged.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.58%. Comparing base (f4543fb) to head (6b3ec83).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #449      +/-   ##
==========================================
+ Coverage   89.56%   89.58%   +0.01%     
==========================================
  Files          28       28              
  Lines        2224     2227       +3     
==========================================
+ Hits         1992     1995       +3     
  Misses        232      232              

[michaelhly]

LGTM!