fix unicode errors on windows 2021

[Remi-Gau]

see #33

https://github.com/Remi-Gau/Octache/actions/runs/4862559339/jobs/8669096325?pr=33#step:5:243

failure: Error using test_renderer>test_renderer_unicode_no_escape (line 123)
  elements are not equal
  
  First input: 1x69 char
  'unicode test (no-escape)
  ===
  <a>(������� ���
  ===
  <a>(������� ���
  ===
  '
  
  Second input: 1x69 char
  'unicode test (no-escape)
  ===
  <a>(������� ���
  ===
  <a>(������� ���
  ===
  '
  
    test_renderer_unicode_no_escape:123 (D:\a\Octache\Octache\tests\test_renderer.m)
  
  failure: Error using test_renderer>test_renderer_unicode_variable (line 137)
  elements are not equal
  
  First input: 1x62 char
  'unicode test (variable)
  ===
  (������� ���
  ===
  (������� ���
  ===
  '
  
  Second input: 1x62 char
  'unicode test (variable)
  ===
  (������� ���
  ===
  (������� ���
  ===
  '
  
    test_renderer_unicode_variable:137 (D:\a\Octache\Octache\tests\test_renderer.m)