Add cargo udeps to CI

[Luni-4]

This PR adds cargo udeps to CI and fixes #726

[codecov-commenter]

Codecov Report

Merging #733 (80a14ba) into master (4eb7370) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #733   +/-   ##
=======================================
  Coverage   37.95%   37.95%           
=======================================
  Files          51       51           
  Lines        6549     6549           
  Branches      962      962           
=======================================
  Hits         2486     2486           
  Misses       3403     3403           
  Partials      660      660           

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