Update file header (#7988)

Author: rubo

.editorconfig

@@ -9,7 +9,7 @@ indent_style = space
 insert_final_newline = true
 trim_trailing_whitespace = true
 
-file_header_template = SPDX-FileCopyrightText: 2024 Demerzel Solutions Limited\nSPDX-License-Identifier: LGPL-3.0-only
+file_header_template = SPDX-FileCopyrightText: 2025 Demerzel Solutions Limited\nSPDX-License-Identifier: LGPL-3.0-only
 
 [*.cs]
 indent_size = 4

CONTRIBUTING.md

@@ -59,7 +59,7 @@ Branch names must follow the `kebab-case` or `snake_case` pattern and be all low
 The following notice must be included as a header in all source files if possible.
 
 ```
-// SPDX-FileCopyrightText: 2024 Demerzel Solutions Limited
+// SPDX-FileCopyrightText: 2025 Demerzel Solutions Limited
 // SPDX-License-Identifier: LGPL-3.0-only
 ```