Update advanced.md

http to https
diff --git a/docs/advanced.md b/docs/advanced.md
index 2a7c482..0e1f812 100644
--- a/docs/advanced.md
+++ b/docs/advanced.md
@@ -2171,7 +2171,7 @@
 
 ```json
 {
-  "$schema": "http://json-schema.org/schema#",
+  "$schema": "https://json-schema.org/schema#",
   "type": "object",
   "definitions": {
     "TestCase": {