Update store plugin's docs to match the new rework

Reference: tauri-apps/plugins-workspace#1860

src/content/docs/plugin/store.mdx

@@ -76,15 +76,12 @@ Install the store plugin to get started.
 <TabItem label="JavaScript">
 
 ```typescript
-import { createStore } from '@tauri-apps/plugin-store';
+import { load } from '@tauri-apps/plugin-store';
 // when using `"withGlobalTauri": true`, you may use
-// const { createStore } = window.__TAURI__.store;
+// const { load } = window.__TAURI__.store;
 
 // create a new store or load the existing one
-const store = await createStore('store.bin', {
-  // we can save automatically after each store modification
-  autoSave: true,
-});
+const store = await load('store.bin');
 
 // Set a value.
 await store.set('some-key', { value: 5 });
@@ -111,7 +108,7 @@ pub fn run() {
     tauri::Builder::default()
         .plugin(tauri_plugin_store::Builder::default().build())
         .setup(|app| {
-            let store = app.handle().store_builder("store.bin").build();
+            let store = app.store("store.json")?;
 
             // Note that values must be serde_json::Value instances,
             // otherwise, they will not be compatible with the JavaScript bindings.
@@ -121,11 +118,6 @@ pub fn run() {
             let value = store.get("some-key").expect("Failed to get value from store");
             println!("{}", value); // {"value":5}
 
-            // You can manually save the store after making changes.
-            // Otherwise, it will save upon graceful exit as described above.
-            store.save()?;
-
-
             Ok(())
         })
         .run(tauri::generate_context!())
@@ -136,6 +128,32 @@ pub fn run() {
 </TabItem>
 </Tabs>
 
+## Migrating from v1 and v2 beta/rc
+
+
+<Tabs>
+<TabItem label="JavaScript">
+
+```diff
+- import { Store } from '@tauri-apps/plugin-store';
++ import { LazyStore } from '@tauri-apps/plugin-store';
+```
+
+</TabItem>
+<TabItem label="Rust">
+
+```diff
+- with_store(app.handle().clone(), stores, path, |store| {
+-     store.insert("some-key".to_string(), json!({ "value": 5 }))?;
+-     Ok(())
+- });
++ let store = app.store(path)?;
++ store.set("some-key".to_string(), json!({ "value": 5 }));
+```
+
+</TabItem>
+</Tabs>
+
 ## Permissions
 
 By default all potentially dangerous plugin commands and scopes are blocked and cannot be accessed. You must modify the permissions in your `capabilities` configuration to enable these.