Use go-digest to validate digests

[imjasonh]

Fixes #1394

cc @wlynch

[codecov-commenter]

Codecov Report

Merging #1395 (4cdfa1a) into main (0c40ec8) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1395   +/-   ##
=======================================
  Coverage   74.11%   74.12%           
=======================================
  Files         113      113           
  Lines        8489     8490    +1     
=======================================
+ Hits         6292     6293    +1     
  Misses       1587     1587           
  Partials      610      610           

Impacted Files	Coverage Δ
pkg/name/digest.go	100.00% <100.00%> (ø)

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