Badges: Fix url arguments for python3

[minextu]

Fixes error when overwriting the badge style with URL arguments

Contributor Checklist:

• I have updated the unit tests
• I have created a file in the master/buildbot/newsfragment directory (and read the README.txt in that directory)
• I have updated the appropriate documentation

[codecov]

Codecov Report

Merging #3832 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3832   +/-   ##
=======================================
  Coverage   88.46%   88.46%           
=======================================
  Files         323      323           
  Lines       34067    34067           
=======================================
  Hits        30139    30139           
  Misses       3928     3928

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