fix reading elements with elset

[lijas]

I created a new branch/pr because the other one was made directly from github.

[codecov-commenter]

Codecov Report

Merging #11 (c0900c9) into main (afa2a02) will increase coverage by 1.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #11      +/-   ##
==========================================
+ Coverage   94.52%   95.62%   +1.09%     
==========================================
  Files           6        6              
  Lines         274      274              
==========================================
+ Hits          259      262       +3     
+ Misses         15       12       -3     

Impacted Files	Coverage Δ
src/abaqusreader.jl	94.44% <100.00%> (+2.38%)	⬆️

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