allow more linkcheck retries

[sappelhoff]

PR Description

relate to

• circleci: sphinx linkcheck keeps failing "too many requests" #1392

let's see if that fixes anything.

Merge checklist

Maintainer, please confirm the following before merging.
If applicable:

• All comments are resolved
• This is not your own PR
• All CIs are happy
• PR title starts with [MRG]
• whats_new.rst is updated
• New contributors have been added to CITATION.cff
• PR description includes phrase "closes <#issue-number>"

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.49%. Comparing base (486597a) to head (9b81cf5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1394   +/-   ##
=======================================
  Coverage   97.49%   97.49%           
=======================================
  Files          40       40           
  Lines        9060     9060           
=======================================
  Hits         8833     8833           
  Misses        227      227           

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