docs(log): update readme code example for v2 (#869)

plugins/log/README.md

@@ -49,14 +49,14 @@ First you need to register the core plugin with Tauri:
 `src-tauri/src/main.rs`
 
 ```rust
-use tauri_plugin_log::{LogTarget};
+use tauri_plugin_log::{Target, TargetKind};
 
 fn main() {
     tauri::Builder::default()
-        .plugin(tauri_plugin_log::Builder::default().targets([
-            LogTarget::LogDir,
-            LogTarget::Stdout,
-            LogTarget::Webview,
+        .plugin(tauri_plugin_log::Builder::new().targets([
+            Target::new(TargetKind::Stdout),
+            Target::new(TargetKind::LogDir { file_name: None }),
+            Target::new(TargetKind::Webview),
         ]).build())
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
@@ -68,7 +68,7 @@ Afterwards all the plugin's APIs are available through the JavaScript guest bind
 ```javascript
 import { trace, info, error, attachConsole } from "@tauri-apps/plugin-log";
 
-// with LogTarget::Webview enabled this function will print logs to the browser console
+// with TargetKind::Webview enabled this function will print logs to the browser console
 const detach = await attachConsole();
 
 trace("Trace");