Rename UpdateResouce to ModifyResource (#4)

For some reason it seems as if UpdateResource is already defined in
some (other) dependency of Pixelarium.
Instead of throwing around platform specific macros to fix the Windows
build for correct mangling, I decided to simply rename the function.

Fixes #3

lib/resources/resource.cpp

@@ -42,7 +42,7 @@ size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<Pixelari
 /// @param id The ID of the resource to update.
 /// @param res A unique pointer to the new resource.
 /// @return True if the resource was updated, false otherwise.
-bool pixelarium::resources::ImageResourcePool::UpdateResource(size_t id, std::unique_ptr<imaging::PixelariumImage> res)
+bool pixelarium::resources::ImageResourcePool::ModifyResource(size_t id, std::unique_ptr<imaging::PixelariumImage> res)
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return false;