Change /contacts/bulk from POST to PUT

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: VarshSuresh

descriptions/0/api.intercom.io.yaml

@@ -7188,7 +7188,7 @@ paths:
               schema:
                 "$ref": "#/components/schemas/error"
   "/contacts/bulk":
-    post:
+    put:
       summary: Bulk update contacts
       parameters:
       - name: Intercom-Version