enables Python 3.10 in jobs

[RobertoPrevato]

No description provided.

[codecov-commenter]

Codecov Report

Merging #197 (39905be) into main (d20e116) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #197   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           47        47           
  Lines         4348      4349    +1     
=========================================
+ Hits          4348      4349    +1     

Impacted Files	Coverage Δ
blacksheep/server/openapi/v3.py	100.00% <100.00%> (ø)
blacksheep/server/controllers.py	100.00% <0.00%> (ø)

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[RobertoPrevato]

Need to change Docker image for the build many linux step, see pypa/manylinux#994