Fix tokenizer_config.json

Without this the tokenizer will not load
See: https://github.com/huggingface/transformers/issues/24318

tokenizer_config.json

@@ -3,7 +3,7 @@
   "add_eos_token": false,
   "bos_token": {
     "__type": "AddedToken",
-    "content": "",
+    "content": "<s>",
     "lstrip": false,
     "normalized": true,
     "rstrip": false,
@@ -12,7 +12,7 @@
   "clean_up_tokenization_spaces": false,
   "eos_token": {
     "__type": "AddedToken",
-    "content": "",
+    "content": "</s>",
     "lstrip": false,
     "normalized": true,
     "rstrip": false,
@@ -24,7 +24,7 @@
   "tokenizer_class": "LlamaTokenizer",
   "unk_token": {
     "__type": "AddedToken",
-    "content": "",
+    "content": "<unk>",
     "lstrip": false,
     "normalized": true,
     "rstrip": false,