fix: error in embedded struct when using option RequiredIfNoDef:true

[bhallionOhbibi]

This PR follows my previous one and fix an issue I spoted when using the option with embedded structs.

Changes

• Fix issue causing parse to fail on embedded struct when using RequiredIfNoDef option.
• Updated test related to RequiredIfNoDef option.

[codecov]

Codecov Report

Merging #191 (852156b) into master (a670257) will increase coverage by 0.90%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #191      +/-   ##
==========================================
+ Coverage   98.18%   99.09%   +0.90%     
==========================================
  Files           2        2              
  Lines         331      331              
==========================================
+ Hits          325      328       +3     
+ Misses          4        2       -2     
+ Partials        2        1       -1     

Impacted Files	Coverage Δ
env.go	99.07% <100.00%> (+0.92%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a670257...852156b. Read the comment docs.

[caarlos0]

thanks!