fix: use MaxCompletionTokens instead of deprecated MaxTokens for OpenAI (#1604)

The OpenAI API deprecated 'max_tokens' parameter in favor of
'max_completion_tokens' for newer models (o1, gpt-4o, etc.).

This change fixes the error:
'Unsupported parameter: max_tokens is not supported with this model.
Use max_completion_tokens instead.'

Refs: https://platform.openai.com/docs/api-reference/chat/create#chat-create-max_tokens

Signed-off-by: Evgenii Kuzakov <evgeniy.kuzakov@csssr.com>
Co-authored-by: Evgenii Kuzakov <evgeniy.kuzakov@csssr.com>

pkg/ai/openai.go

@@ -95,7 +95,7 @@ func (c *OpenAIClient) GetCompletion(ctx context.Context, prompt string) (string
 			},
 		},
 		Temperature:      c.temperature,
-		MaxTokens:        maxToken,
+		MaxCompletionTokens: maxToken,
 		PresencePenalty:  presencePenalty,
 		FrequencyPenalty: frequencyPenalty,
 		TopP:             c.topP,