Support sfml 3.0.0

[chenrui333]

👋 I saw the project has already supported sfml v3, but there is still some issue I see in the cmake build process as below:

  Searching for SFML 3...
  
  -- Requested SFML configuration (Shared) was not found
  CMake Warning at cmake/Dependencies.cmake:68 (find_package):
    Found package configuration file:
  
      /opt/homebrew/lib/cmake/SFML/SFMLConfig.cmake
  
    but it set SFML_FOUND to FALSE so package "SFML" is considered to be NOT
    FOUND.
  Call Stack (most recent call first):
    cmake/Dependencies.cmake:93 (tgui_find_dependency_sfml)
    src/Backend/CMakeLists.txt:175 (tgui_add_dependency_sfml)
    src/CMakeLists.txt:517 (include)
  
  
  CMake Error at cmake/Dependencies.cmake:80 (message):
    CMake couldn't find SFML.
  
    Set SFML_DIR to the directory containing SFMLConfig.cmake (usually
    something like SFML_ROOT/lib/cmake/SFML)
  
  Call Stack (most recent call first):
    cmake/Dependencies.cmake:93 (tgui_find_dependency_sfml)
    src/Backend/CMakeLists.txt:175 (tgui_add_dependency_sfml)
    src/CMakeLists.txt:517 (include)

full build log, https://github.com/Homebrew/homebrew-core/actions/runs/12475120895/job/34818182416
relates to Homebrew/homebrew-core#202104

[texus]

Is SFML being build statically?
In SFML 3 they did change the default from dynamic to static libraries. The message "Requested SFML configuration (Shared) was not found" suggests that it did find a static configuration (but it is ignoring it because TGUI builds shared libs by default).

EDIT: I checked and brew install sfml does install .a files instead of .dylib like sfml@2. Is this intentional and do you also want to build TGUI statically? Either way it might be a good idea to specify BUILD_SHARED_LIBS (or TGUI_SHARED_LIBS) when building TGUI, because I might change the default in the future as well to match with SFML's new behavior.

[texus]

SFML should be installed as a shared library again now that Homebrew/homebrew-core#202492 is merged.
That will probably have fixed this issue.