Wire up iTunesGrouping to the ID3TagContentReader

[jverkoey]

The frame key was already defined, there just wasn't a convenience method exposed on ID3TagContentReader.

Provide a general summary of your changes

Types of changes

• Bug fix 🐛 (non-breaking change which fixes an issue)
• New feature ✨ (non-breaking change which adds functionality)
• Breaking change 💥 (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project 🍻.
• I have read the CONTRIBUTING document 👥.
• I have added tests to cover my changes 🎉.
• All new and existing tests passed ✅.

[chicio]

Thank you for your contribution @jverkoey 🙏. I will merge and release a new version of ID3TagEditor in the following days. 🚀

[codecov]

Codecov Report

Merging #92 (d2d9d66) into main (d2906ef) will decrease coverage by 0.04%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main      #92      +/-   ##
==========================================
- Coverage   94.96%   94.91%   -0.05%     
==========================================
  Files         153      153              
  Lines        4266     4268       +2     
==========================================
  Hits         4051     4051              
- Misses        215      217       +2     

Impacted Files	Coverage Δ
Source/Tag/ID3TagContentReader.swift	87.71% <0.00%> (-1.57%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[chicio]

Going to release today. I will add you to the contributors. Thanks again for the support 🙏

[jverkoey]

Thank you!