fix(convert): correctly quote paths when using ffmpeg on Windows

With the current version of ffmpeg on Windows, the list file must enclosed by single quotes.

Author: yang-fighter

manim_slides/config.py

@@ -206,7 +206,7 @@ def concat_animations(self, dest: Optional[str] = None) -> "PresentationConfig":
                 dest_path = merge_basenames(files)
 
                 f = tempfile.NamedTemporaryFile(mode="w", delete=False)
-                f.writelines(f"file {os.path.abspath(path)}\n" for path in files)
+                f.writelines(f"file '{os.path.abspath(path)}'\n" for path in files)
                 f.close()
 
                 command = [