Bugfix/increase tokens (#132)

* feat(api.ts): add support for OPENAI_MAX_TOKENS environment variable
feat(config.ts): add OPENAI_MAX_TOKENS to CONFIG_KEYS and configValidators

* 2.0.2

* 2.0.3

* docs(README.md): add GPT-4 usage instructions and mention the cost difference compared to GPT-3.5-turbo

---------

Co-authored-by: di-sukharev <dim.sukharev@gmail.com>

src/api.ts

@@ -13,6 +13,7 @@ const config = getConfig();
 
 let apiKey = config?.OPENAI_API_KEY;
 let basePath = config?.OPENAI_BASE_PATH;
+let maxTokens = config?.OPENAI_MAX_TOKENS;
 
 const [command, mode] = process.argv.slice(2);
 
@@ -53,7 +54,7 @@ class OpenAi {
         messages,
         temperature: 0,
         top_p: 0.1,
-        max_tokens: 196
+        max_tokens: maxTokens ?? 196
       });
 
       const message = data.choices[0].message;