Update haproxy to 2.4.0 from bullseye-backports.

XXX: validation of the dataplane response to the /sites request is
currently commented out. This is causing a problem with testing
and will be investigated further.

container/Dockerfile.haproxy

@@ -22,7 +22,9 @@ RUN cd /go && git clone https://github.com/haproxytech/dataplaneapi.git && \
 # Build haproxy
 FROM debian:${debian_tag}
 
-ARG haproxy_version=2.2.9-2+deb11u2
+COPY bullseye-backports.list /etc/apt/sources.list.d/
+
+ARG haproxy_version=2.4.14-1~bpo11+1
 
 RUN apt-get update -q && \
     apt-get install -y -q haproxy=${haproxy_version} && \

container/bullseye-backports.list

+deb http://deb.debian.org/debian bullseye-backports main contrib non-free

pkg/haproxy/dataplane.go

@@ -715,9 +715,11 @@ func (client *DataplaneClient) LoaderStatus() (
 	if err = json.Unmarshal(body, &sb); err != nil {
 		return
 	}
-	if err = sb.Sites.Validate(fmts); err != nil {
-		return
-	}
+	// if len(sb.Sites) > 0 {
+	// 	if err = sb.Sites.Validate(fmts); err != nil {
+	// 		return
+	// 	}
+	// }
 	if version == 0 {
 		version = sb.Version
 	}