Change project license from AGPL-3.0 to GPL-3.0

Author: Taboulet

flatpak/io.github.taboulet.BiggerTask.metainfo.xml

@@ -6,7 +6,7 @@
 
   <developer_name>Taboulet</developer_name>
   <metadata_license>CC0-1.0</metadata_license>
-  <project_license>AGPL-3.0-or-later</project_license>
+  <project_license>GPL-3.0-only</project_license>
   <url type="homepage">https://github.com/Taboulet/BiggerTask</url>
 
   <description>