c code generator support IA5String for uper encoding

[sailing0505]

This enchancement is to generate the C code for IA5String for UPER encoding
for example: foo.asn
FOO DEFINITIONS AUTOMATIC TAGS ::=
BEGIN
DATAS ::= SEQUENCE {
fixedName IA5String (SIZE(3)),
variableName IA5String (SIZE(1..20))
}
END

execute: asn1tools generate_c_source --codec uper --generate-fuzzer foo.asn

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 34.82%. Comparing base (c890898) to head (dac1694).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #170   +/-   ##
=======================================
  Coverage   34.82%   34.82%           
=======================================
  Files           7        7           
  Lines        8666     8666           
=======================================
  Hits         3018     3018           
  Misses       5648     5648           

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[coveralls]

coverage: 96.274% (-0.2%) from 96.473%
when pulling dac1694 on sailing0505:master
into c890898 on eerimoq:master.

[Futsch1]

Hi sailing0505,

Thanks for the pull request.

The changes look okay at first glance, I will perform a review once you add some tests for the new functionality to the PR.

[TheSkorm]

Just attempted to use asn1tools for c code generation with ia5string and ran into this. would be good to have in mainline