register: sajid.json add verification string

domains/_github-pages-challenge-sajidshahriar72543.sajid.json

@@ -0,0 +1,9 @@
+{
+    "owner": {
+        "username": "sajidshahriar72543",
+        "email": "sazidshahriar39@gmail.com"
+    },
+    "record": {
+        "TXT": "f5a9c65aff454e5a69870bc977a2df"
+    }
+}