async getAccessTokenFromCode(authData) {
    const tokenUrl = 'https://github.com/login/oauth/access_token';
    const response = await fetch(tokenUrl, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Accept: 'application/json',
      },
      body: JSON.stringify({
        client_id: this.clientId,
        client_secret: this.clientSecret,
        code: authData.code,
      }),
    });

    if (!response.ok) {
      throw new Parse.Error(Parse.Error.VALIDATION_ERROR, `Failed to exchange code for token: ${response.statusText}`);
    }

    const data = await response.json();
    if (data.error) {
      throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, data.error_description || data.error);
    }

    return data.access_token;
  }
Parse Server authentication adapter for GitHub.
@class GitHubAdapter
@param {Object} options - The adapter configuration options.
@param {string} options.clientId - The GitHub App Client ID. Required for secure authentication.
@param {string} options.clientSecret - The GitHub App Client Secret. Required for secure authentication.
@param {boolean} [options.enableInsecureAuth=false] - **[DEPRECATED]** Enable insecure authentication (not recommended).

@param {Object} authData - The authentication data provided by the client.
@param {string} authData.code - The authorization code from GitHub. Required for secure authentication.
@param {string} [authData.id] - **[DEPRECATED]** The GitHub user ID (required for insecure authentication).
@param {string} [authData.access_token] - **[DEPRECATED]** The GitHub access token (required for insecure authentication).

@description
## Parse Server Configuration
* To configure Parse Server for GitHub authentication, use the following structure:
```json
{
 "auth": {
  "github": {
    "clientId": "12345",
    "clientSecret": "abcde"
  }
}
```

The GitHub adapter exchanges the `authData.code` provided by the client for an access token using GitHub's OAuth API. The following `authData` field is required:
- `code`

## Insecure Authentication (Not Recommended)
Insecure authentication uses the `authData.id` and `authData.access_token` provided by the client. This flow is insecure, deprecated, and poses potential security risks. The following `authData` fields are required:
- `id` (**[DEPRECATED]**): The GitHub user ID.
- `access_token` (**[DEPRECATED]**): The GitHub access token.
To configure Parse Server for insecure authentication, use the following structure:
```json
{
 "auth": {
   "github": {
   "enableInsecureAuth": true
 }
}
```

### Deprecation Notice
The `enableInsecureAuth` option and insecure `authData` fields (`id`, `access_token`) are deprecated and will be removed in future versions. Use secure authentication with `clientId` and `clientSecret`.

@example <caption>Secure Authentication Example</caption>
// Example authData for secure authentication:
const authData = {
  github: {
    code: "abc123def456ghi789"
  }
};

@example <caption>Insecure Authentication Example (Not Recommended)</caption>
// Example authData for insecure authentication:
const authData = {
  github: {
    id: "1234567",
    access_token: "abc123def456ghi789" // Deprecated.
  }
};

@note `enableInsecureAuth` will be removed in future versions. Use secure authentication with `clientId` and `clientSecret`.
@note Secure authentication exchanges the `code` provided by the client for an access token using GitHub's OAuth API.

@see {@link https://docs.github.com/en/developers/apps/authorizing-oauth-apps GitHub OAuth Documentation}