README: display clear errors in the example

Author: nim65s

README.md

@@ -93,17 +93,18 @@ async fn main() {
         }.into_query("weather"),
     );
 
-    let write_result = client
-        .query(weather_readings)
-        .await;
-    assert!(write_result.is_ok(), "Write result was not okay");
+    if let Err(e) = client.query(weather_readings).await {
+        println!("Error writing result: {e}");
+        return;
+    }
 
     // Let's see if the data we wrote is there
     let read_query = ReadQuery::new("SELECT * FROM weather");
 
-    let read_result = client.query(read_query).await;
-    assert!(read_result.is_ok(), "Read result was not ok");
-    println!("{}", read_result.unwrap());
+    match client.query(read_query).await {
+        Ok(read_result) => println!("{}", read_result),
+        Err(e) => println!("Error reading result: {e}"),
+    }
 }
 ```