feat: try to unwrap external errors during error wrapping

[morningvera]

closes #37

[codecov-io]

Codecov Report

Merging #80 into master will increase coverage by 0.06%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #80      +/-   ##
==========================================
+ Coverage   98.85%   98.91%   +0.06%     
==========================================
  Files           3        3              
  Lines         261      277      +16     
==========================================
+ Hits          258      274      +16     
  Misses          1        1              
  Partials        2        2

Impacted Files	Coverage Δ
eris.go	100% <100%> (ø)	⬆️

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[sum2000]

I am on the fence about this approach, it feels forced and hard to manage, makes me think if we really should support it if this is the only way to do it