Use latest upload/download-artifact action version

[Sovietaced]

Version 2 of the upload-artifact GitHub action has been deprecated for a while and recently updated to fail builds.

This updates it to the latest version so that the build no longer fails.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 36.22%. Comparing base (e67aae0) to head (3ba5810).
Report is 159 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5743   +/-   ##
=======================================
  Coverage   36.21%   36.22%           
=======================================
  Files        1303     1303           
  Lines      109644   109644           
=======================================
+ Hits        39710    39715    +5     
+ Misses      65810    65805    -5     
  Partials     4124     4124           

Flag	Coverage Δ
unittests-datacatalog	51.37% <ø> (ø)
unittests-flyteadmin	55.63% <ø> (+0.03%)	⬆️
unittests-flytecopilot	12.17% <ø> (ø)
unittests-flytectl	62.21% <ø> (ø)
unittests-flyteidl	7.12% <ø> (ø)
unittests-flyteplugins	53.35% <ø> (ø)
unittests-flytepropeller	41.75% <ø> (ø)
unittests-flytestdlib	55.19% <ø> (-0.03%)	⬇️

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