[3.7] Fix CI badge in docs (#5252)

[aio-libs-github-bot]

Backports the following commits to 3.7:

• Fix CI badge in docs (Fix CI badge in docs #5252)

[codecov]

Codecov Report

Merging #5254 (29fbb5d) into 3.7 (29d167e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              3.7    #5254   +/-   ##
=======================================
  Coverage   97.55%   97.55%           
=======================================
  Files          44       44           
  Lines        8818     8818           
  Branches     1419     1419           
=======================================
  Hits         8602     8602           
  Misses        101      101           
  Partials      115      115           

Flag	Coverage Δ
unit	97.39% <ø> (ø)

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