Add test for custom Column attributes (charset, collation)

[roxblnfk]

🔍 What was changed

• Set min php version to 8.1
• Add unit test verifying charset/collation pass through Column variadic ...$attributes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.87%. Comparing base (7564927) to head (237760f).
⚠️ Report is 2 commits behind head on 4.x.

Additional details and impacted files

@@            Coverage Diff            @@
##                4.x     #121   +/-   ##
=========================================
  Coverage     91.87%   91.87%           
  Complexity      324      324           
=========================================
  Files            38       38           
  Lines           825      825           
=========================================
  Hits            758      758           
  Misses           67       67           

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