Add new openai 0613 model costs (#6110)

Added costs for gpt-4-32k-0613, gpt-4-0613, gpt-3.5-turbo-16k,
gpt-3.5-turbo-0613, and gpt-3.5-turbo-16k-0613 to openai_info callback
based on this [OpenAI
post](https://openai.com/blog/function-calling-and-other-api-updates)

@agola11

langchain/callbacks/openai_info.py

@@ -13,8 +13,13 @@ MODEL_COST_PER_1K_TOKENS = {
     "gpt-4-32k-0314": 0.06,
     "gpt-4-32k-completion": 0.12,
     "gpt-4-32k-0314-completion": 0.12,
+    "gpt-4-0613": 0.06,
+    "gpt-4-32k-0613": 0.12,
     "gpt-3.5-turbo": 0.002,
     "gpt-3.5-turbo-0301": 0.002,
+    "gpt-3.5-turbo-16k": 0.004,
+    "gpt-3.5-turbo-0613": 0.002,
+    "gpt-3.5-turbo-16k-0613": 0.004,
     "text-ada-001": 0.0004,
     "ada": 0.0004,
     "text-babbage-001": 0.0005,