Update config for depth-4 architecture

config.json

@@ -1,9 +1,9 @@
 {
   "sequence_len": 2048,
   "vocab_size": 4096,
-  "n_layer": 8,
-  "n_head": 8,
-  "n_kv_head": 4,
-  "n_embd": 512,
+  "n_layer": 4,
+  "n_head": 4,
+  "n_kv_head": 2,
+  "n_embd": 256,
   "window_pattern": "SSSL"
 }