Add a step to smoke test the sdist and wheel packages

[vEpiphyte]

This tests the installation of the sdist and wheel packages before they are published to pypi

[codecov]

Codecov Report

Merging #1853 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1853      +/-   ##
==========================================
+ Coverage   96.28%   96.29%   +0.01%     
==========================================
  Files         141      141              
  Lines       27610    27610              
==========================================
+ Hits        26585    26588       +3     
+ Misses       1025     1022       -3     

Flag	Coverage Δ
#linux	96.29% <ø> (+0.01%)	⬆️
#linux_replay	66.68% <ø> (+0.08%)	⬆️

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Impacted Files	Coverage Δ
synapse/lib/spawn.py	95.48% <0.00%> (+0.96%)	⬆️

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