modrinth: rename input to MODRINTH_MODPACK (#2334)

examples/mods-file/docker-compose.yml

@@ -0,0 +1,19 @@
+version: '3.8'
+
+services:
+  mc:
+    image: itzg/minecraft-server
+    environment:
+      EULA: "true"
+      TYPE: FORGE
+      VERSION: 1.15.2
+      MODS_FILE: /extras/mods.txt
+      REMOVE_OLD_MODS: "true"
+    ports:
+      - "25565:25565"
+    volumes:
+      - data:/data
+      - ./mods.txt:/extras/mods.txt:ro
+
+volumes:
+  data: