plugins/slurm: Add copyright notice

/******************************************************************************

 * Copyright 2022-2023, Inria, France.

 * Copyright 2023, Barcelona Supercomputing Center (BSC), Spain.

 * All rights reserved.

 *

 * This software was partially supported by the EuroHPC-funded project ADMIRE

 *   (Project ID: 956748, https://www.admire-eurohpc.eu).

 *

 * This file is part of scord.

 *

 * scord is free software: you can redistribute it and/or modify

 * it under the terms of the Lesser GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * scord is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the Lesser GNU General Public License

 * along with scord.  If not, see <https://www.gnu.org/licenses/>.

 *

 * SPDX-License-Identifier: LGPL-3.0-or-later

 *****************************************************************************/

#include <errno.h>

#include <stdint.h>				/* SIZE_MAX, uint32_t, etc. */

#include <stdlib.h>				/* strtoul, getenv, reallocarray */