add missing constraint to "header"

https://spec.openapis.org/oas/v3.1.0#headerObject

Author: karenetheridge

schemas/v3.1/schema.json

@@ -945,6 +945,18 @@
           "$ref": "#/$defs/content"
         }
       },
+      "oneOf": [
+        {
+          "required": [
+            "schema"
+          ]
+        },
+        {
+          "required": [
+            "content"
+          ]
+        }
+      ],
       "dependentSchemas": {
         "schema": {
           "properties": {

schemas/v3.1/schema.yaml

@@ -641,6 +641,11 @@ $defs:
         $dynamicRef: '#meta'
       content:
         $ref: '#/$defs/content'
+    oneOf:
+      - required:
+        - schema
+      - required:
+        - content
     dependentSchemas:
       schema:
         properties: