fix: don't use deprecated cast name (integer)

[HypeMC]

The (integer) cast name has been deprecated in PHP 8.5, (int) should be used instead.

[codecov]

Codecov Report

❌ Patch coverage is 99.21875% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 92.01%. Comparing base (a07c267) to head (1ba08bc).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/CrowdinApiClient/Model/SourceString.php	85.72%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #245   +/-   ##
=========================================
  Coverage     92.01%   92.01%           
  Complexity     1557     1557           
=========================================
  Files           146      146           
  Lines          4167     4167           
=========================================
  Hits           3834     3834           
  Misses          333      333           

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[andrii-bodnar]

Looks good to me! @HypeMC thanks for the contribution!