Add AIProxy support for setting custom ClientID (#52)

Author: lzell

README.md

@@ -123,18 +123,18 @@ For example, a `429` means that your requests are being rate limited.
 The `APIError` type has a case `responseUnsuccessful` with two associated values: a `description` and `statusCode`.
 Here is a usage example using the chat completion API:
 
-```
-      let service = OpenAIServiceFactory.service(apiKey: apiKey)
-      let parameters = ChatCompletionParameters(messages: [.init(role: .user, content: .text("hello world"))],
-                                                model: .gpt4o)
-      do {
-         let choices = try await service.startChat(parameters: parameters).choices
-         // Work with choices
-      } catch APIError.responseUnsuccessful(let description, let statusCode) {
-         print("Network error with status code: \(statusCode) and description: \(description)")
-      } catch {
-         print(error.localizedDescription)
-      }
+```swift
+let service = OpenAIServiceFactory.service(apiKey: apiKey)
+let parameters = ChatCompletionParameters(messages: [.init(role: .user, content: .text("hello world"))],
+                                          model: .gpt4o)
+do {
+   let choices = try await service.startChat(parameters: parameters).choices
+   // Work with choices
+} catch APIError.responseUnsuccessful(let description, let statusCode) {
+   print("Network error with status code: \(statusCode) and description: \(description)")
+} catch {
+   print(error.localizedDescription)
+}
 ```