Use dualstack endpoints in doc tests

[manuelpelloni]

Closes #23

[codecov]

Codecov Report

Merging #36 (99a8681) into main (adaf065) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main      #36   +/-   ##
=======================================
  Coverage   91.84%   91.84%           
=======================================
  Files          26       26           
  Lines        1250     1250           
=======================================
  Hits         1148     1148           
  Misses        102      102           

Impacted Files	Coverage Δ
src/bucket.rs	98.21% <100.00%> (ø)

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