Update tokenizer_config.json

Following https://huggingface.co/codellama/CodeLlama-34b-hf/discussions/9 to support usage with ctranslate2
cc:

@ctranslate2-4you

tokenizer_config.json

@@ -1,6 +1,7 @@
 {
   "add_bos_token": true,
   "add_eos_token": false,
+  "additional_special_tokens": [],
   "bos_token": {
     "__type": "AddedToken",
     "content": "<s>",
@@ -9,6 +10,8 @@
     "rstrip": false,
     "single_word": false
   },
+  "eot_token": null,
+  "fill_token": "<FILL_ME>",
   "clean_up_tokenization_spaces": false,
   "eos_token": {
     "__type": "AddedToken",
@@ -19,9 +22,13 @@
     "single_word": false
   },
   "legacy": null,
+  "middle_token": null,
   "model_max_length": 1000000000000000019884624838656,
   "pad_token": null,
+  "prefix_token": null,
   "sp_model_kwargs": {},
+  "suffix_first": false,
+  "suffix_token": null,
   "tokenizer_class": "CodeLlamaTokenizer",
   "unk_token": {
     "__type": "AddedToken",