[ci skip] Add license notice to README.md

Author: esotericenderman

README.md

@@ -4,6 +4,16 @@
 
 > A Minecraft Paper plugin that adds some SCPs to the game.
 
+## License
+
+[SCP Plugin](./) © 2024-2025 [Esoteric Enderman](https://enderman.dev)
+
+This program is free software: you can redistribute it and/or modify it under the terms of the [GNU General Public License](./LICENSE) as published by the [Free Software Foundation](https://www.fsf.org/), either [version 3](./LICENSE) of the License, or (at your option) any later version.
+
+This program 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](./LICENSE) for more details.
+
+You should have received a copy of the [GNU General Public License](./LICENSE) along with this program. If not, see <[gnu.org/licenses](https://www.gnu.org/licenses/)>.
+
 ## Topics
 
 plugin minecraft scp minecraft-plugin scp-foundation paper-plugin minecraft-plugins papermc-plugin scps minecraft-paper paper-plugins minecraft-paper-plugin minecraft-paper-plugins minecraft-papermc-plugin minecraft-papermc scp-018 scp-268 minecraft-scp scp-minecraft minecraft-scp-plugin