add player as property

samples/verg.yml

@@ -1 +1,2 @@
 name: Verg-La
+player: Yanick

schemas-yaml/character.yml

@@ -1,3 +1,11 @@
 $id: https://hyperboria.babyl.ca/character.json
 title: Hyperboria character sheet
 type: object
+additionalProperties: false
+required:
+    - name
+    - player
+properties:
+    name: &string
+        type: string
+    player: *string