Add support for FreeBSD

Signed-off-by: Uilian Ries <uilianries@gmail.com>

Author: uilianries

examples/tools/system/package_manager/conanfile.py

@@ -20,7 +20,7 @@ def package_id(self):
         self.info.clear()
 
     def validate(self):
-        supported_os = ["Linux", "Macos"]
+        supported_os = ["Linux", "Macos", "FreeBSD"]
         if self.settings.os not in supported_os:
             raise ConanInvalidConfiguration(f"{self.ref} wraps a system package only supported by {supported_os}.")