Update http4s-blaze-client, http4s-circe, ... to 0.21.5

[BenFradet]

No description provided.

[codecov]

Codecov Report

Merging #518 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #518   +/-   ##
=======================================
  Coverage   90.45%   90.45%           
=======================================
  Files          24       24           
  Lines         618      618           
  Branches        1        1           
=======================================
  Hits          559      559           
  Misses         59       59           

Impacted Files	Coverage Δ
...ub4s/src/main/scala/github4s/http/HttpClient.scala	87.50% <100.00%> (ø)

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