Fix phpdoc on createMock()

[ro0NL]

Hi,

This fixes an error raised by phpstan (static analysis)

Parameter 1 $originalClassName of method PHPUnit\Framework\TestCase::createMock() expects string, array<int, string> given.

And can be traced back to https://github.com/sebastianbergmann/phpunit/blob/master/src/Framework/TestCase.php#L1198

[codecov-io]

Codecov Report

Merging #2963 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #2963   +/-   ##
=========================================
  Coverage     80.32%   80.32%           
  Complexity     2816     2816           
=========================================
  Files           107      107           
  Lines          7429     7429           
=========================================
  Hits           5967     5967           
  Misses         1462     1462

Impacted Files	Coverage Δ	Complexity Δ
src/Framework/TestCase.php	66.46% <ø> (ø)	309 <0> (ø)	⬇️

---

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 eae3fa3...0bcbff5. Read the comment docs.