[Copyright] Fix file headers

[matteobettini]

FIxes #169

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.30%. Comparing base (6761c7a) to head (1973d44).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #171   +/-   ##
=======================================
  Coverage   87.30%   87.30%           
=======================================
  Files          93       93           
  Lines       10441    10441           
=======================================
  Hits         9115     9115           
  Misses       1326     1326           

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