go.mod: upgrade to NeoFS SDK RC15

[roman-khimov]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.05%. Comparing base (f32e48a) to head (03ee4ba).
⚠️ Report is 15 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4028      +/-   ##
==========================================
+ Coverage   82.04%   82.05%   +0.01%     
==========================================
  Files         351      351              
  Lines       50127    50133       +6     
==========================================
+ Hits        41125    41135      +10     
+ Misses       7268     7265       -3     
+ Partials     1734     1733       -1     

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[AnnaShaleva]

Linter for scripts is failing, probably need to go mod tidy.

Otherwise LGTM.

[roman-khimov]

replace gives interesting side-effects even though it's a separate go.mod.