fix(swagger): use correct serial_out_path name in PUT /serial

We mistakenly added it as `output_path` rather than `serial_out_path`.

Signed-off-by: Riccardo Mancini <[email protected]>

Author: Manciukic

src/firecracker/swagger/firecracker.yaml

@@ -1421,7 +1421,7 @@ definitions:
     description:
       The configuration of the serial device
     properties:
-      output_path:
+      serial_out_path:
         type: string
         description: Path to a file or named pipe on the host to which serial output should be written.