[1.x] chore: prep 1.8.12 release (#4335)

* chore: prep 1.8.12 release

* chore: update LICENSE.md to current year

Author: imorland

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2020-2021 Stichting Flarum (Flarum Foundation)
+Copyright (c) 2020-2026 Stichting Flarum (Flarum Foundation)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal