add clear_cache function to JMClient

jm_client_core/src/client.rs

@@ -36,6 +36,11 @@ impl JMClient {
         JMClientBuilder::default()
     }
 
+    /// clears the cache. all requests will be made again after this has been called.
+    pub async fn clear_cache(&mut self) {
+        self.cache.lock().await.clear();
+    }
+
     async fn get_api_json<R, T, F>(
         &self,
         cache: &OnceCell<Arc<T>>,
@@ -104,6 +109,14 @@ struct Cache {
     memes: OnceCell<Arc<Vec<Meme>>>,
 }
 
+impl Cache {
+    fn clear(&mut self) {
+        self.users = OnceCell::default();
+        self.cats = OnceCell::default();
+        self.memes = OnceCell::default();
+    }
+}
+
 #[derive(Debug, Default)]
 pub struct JMClientBuilder {
     client: Option<reqwest::Client>,