Add DingTalk provider

[naokij]

Description

This PR adds OAuth2 authentication support for DingTalk. DingTalk is an enterprise collaboration and communication platform developed by Alibaba Group and is widely used in China.

Main Features

• Supports the standard OAuth2 authentication process.
• Supports company ID verification (optional).
• Supports token refresh.
• Provides detailed documentation and examples.
• Adds comprehensive testing.

Configuration Example

dingTalkProvider := dingtalk.New(
    os.Getenv("DINGTALK_KEY"), 
    os.Getenv("DINGTALK_SECRET"), 
    "http://localhost:3000/auth/dingtalk/callback", 
    os.Getenv("DINGTALK_CORP_ID"), // Used for company verification. Can be set as an empty string if not needed.
    "openid", 
    "corpid" // Must be included in the scope when company verification is required.
)
goth.UseProviders(dingTalkProvider)

Testing

Test cases have been added to cover the main functions.

Related Links

• DingTalk Open Platform
• DingTalk OAuth2 Documentation