reconstruct priv key better

[decentralgabe]

the key type was not maintained, leading to signing errors

[codecov-commenter]

Codecov Report

Merging #211 (c3d5e9c) into main (56fc273) will increase coverage by 0.23%.
The diff coverage is 90.24%.

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
+ Coverage   58.04%   58.27%   +0.23%     
==========================================
  Files          33       33              
  Lines        3813     3841      +28     
==========================================
+ Hits         2213     2238      +25     
- Misses       1229     1232       +3     
  Partials      371      371              

Impacted Files	Coverage Δ
crypto/jwt.go	39.32% <0.00%> (ø)
crypto/keys.go	83.51% <91.43%> (+1.01%)	⬆️
crypto/models.go	11.11% <100.00%> (ø)
cryptosuite/jsonwebkey2020.go	50.38% <100.00%> (ø)
did/key.go	67.27% <100.00%> (ø)
did/model.go	100.00% <100.00%> (ø)
did/util.go	53.39% <100.00%> (ø)