Update axum to 0.8.1 (#10332)

Only a few things that needed updating:

- async_trait was removed
- Message::Text takes a Utf8Bytes object instead of a String

Signed-off-by: Tristan Partin <tristan@neon.tech>
Co-authored-by: Conrad Ludgate <connor@neon.tech>

libs/vm_monitor/src/dispatcher.rs

@@ -7,7 +7,7 @@
 //! (notifying it of upscale).
 
 use anyhow::{bail, Context};
-use axum::extract::ws::{Message, WebSocket};
+use axum::extract::ws::{Message, Utf8Bytes, WebSocket};
 use futures::{
     stream::{SplitSink, SplitStream},
     SinkExt, StreamExt,
@@ -82,21 +82,21 @@ impl Dispatcher {
 
         let highest_shared_version = match monitor_range.highest_shared_version(&agent_range) {
             Ok(version) => {
-                sink.send(Message::Text(
+                sink.send(Message::Text(Utf8Bytes::from(
                     serde_json::to_string(&ProtocolResponse::Version(version)).unwrap(),
-                ))
+                )))
                 .await
                 .context("failed to notify agent of negotiated protocol version")?;
                 version
             }
             Err(e) => {
-                sink.send(Message::Text(
+                sink.send(Message::Text(Utf8Bytes::from(
                     serde_json::to_string(&ProtocolResponse::Error(format!(
                         "Received protocol version range {} which does not overlap with {}",
                         agent_range, monitor_range
                     )))
                     .unwrap(),
-                ))
+                )))
                 .await
                 .context("failed to notify agent of no overlap between protocol version ranges")?;
                 Err(e).context("error determining suitable protocol version range")?
@@ -126,7 +126,7 @@ impl Dispatcher {
 
         let json = serde_json::to_string(&message).context("failed to serialize message")?;
         self.sink
-            .send(Message::Text(json))
+            .send(Message::Text(Utf8Bytes::from(json)))
             .await
             .context("stream error sending message")
     }