fix(deps): update module github.com/openai/openai-go to v1.12.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
github.com/openai/openai-go	v1.10.1 → v1.12.0

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Release Notes

openai/openai-go (github.com/openai/openai-go)

v1.12.0

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Full Changelog: v1.12.0...v2.0.0

Breaking changes

With the launch of custom tools in Chat Completions, function tools have been renamed to clarify the difference between the two.

ChatCompletionToolParam has become a union and is now named ChatCompletionToolUnionParam.

Older versions of the SDK used function tools: to migrate

- openai.ChatCompletionToolParam{
-  Function: openai.FunctionDefinitionParam{
+ openai.ChatCompletionFunctionTool(
+  openai.FunctionDefinitionParam{
    Name:        "get_weather",
    Description: openai.String("Get weather at the given location"),
    Parameters: openai.FunctionParameters{ … },
+  },
+ )
- },

Features

• api: adds GPT-5 and new API features: platform.openai.com/docs/guides/gpt-5 (af46c88)
• api: manual updates (219f209)
• client: remove HTML escaping in JSON (aea5ebc)
• client: rename union helpers (645e881)
• client: support optional json html escaping (1d2336b)

Bug Fixes

• client: revert path param changes (9239f06)

Chores

• change readme warning and minimum version (1d0e22f)
• document breaking changes (afaa2b8)
• migrate examples (9c57dd7)

v1.11.1

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Full Changelog: v1.11.1...v1.12.0

Features

• api: manual updates (16312ea)

Chores

• client: refactor streaming slightly to better future proof it (0b9cb85)

v1.11.0

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Full Changelog: v1.11.0...v1.11.1

Bug Fixes

• client: process custom base url ahead of time (cc1c23e)

Chores

• api: event shapes more accurate (2acd10d)

v1.10.3

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Full Changelog: v1.10.3...v1.11.0

Features

• api: manual updates (97ed7fd)

v1.10.2

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Full Changelog: v1.10.2...v1.10.3

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