fix: record fields avro schema creation (#382)

[dada-engineer]

Fixes #382

[dada-engineer]

This needs some rework as now it would break union types

[dada-engineer]

Changed the solution to something that renders only actual values of the default into the schema. This should work and does not break other existing stuff. 🤞🏻

[codecov]

Codecov Report

Merging #383 (ef14661) into master (18e942e) will increase coverage by 0.00%.
Report is 2 commits behind head on master.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #383   +/-   ##
=======================================
  Coverage   99.26%   99.26%           
=======================================
  Files          20       20           
  Lines        1487     1490    +3     
  Branches      271      272    +1     
=======================================
+ Hits         1476     1479    +3     
  Misses          3        3           
  Partials        8        8           

Files Changed	Coverage Δ
dataclasses_avroschema/fields/fields.py	99.00% <100.00%> (+<0.01%)	⬆️
dataclasses_avroschema/schema_definition.py	98.82% <100.00%> (+0.02%)	⬆️