proxy: v2.121.0 (#5253)

This release changes error handling to teardown the server-side
connection when an unexpected error is encountered.

Additionally, the outbound TCP routing stack can now skip redundant
service discovery lookups when profile responses include endpoint
information.

Finally, the cache implementation has been updated to reduce latency by
removing unnecessary buffers.

---

* h2: enable HTTP/2 keepalive PING frames (linkerd/linkerd2-proxy#737)
* actions: Add timeouts to GitHub actions (linkerd/linkerd2-proxy#738)
* outbound: Skip endpoint resolution on profile hint (linkerd/linkerd2-proxy#736)
* Add a FromStr for dns::Name (linkerd/linkerd2-proxy#746)
* outbound: Avoid redundant TCP endpoint resolution (linkerd/linkerd2-proxy#742)
* cache: Make the cache cloneable with RwLock (linkerd/linkerd2-proxy#743)
* http: Teardown serverside connections on error (linkerd/linkerd2-proxy#747)

.proxy-version

@@ -1 +1 @@
-v2.119.0
+v2.121.0

controller/api/destination/server.go

@@ -203,6 +203,9 @@ func (s *server) GetProfile(dest *pb.GetDestination, stream pb.Destination_GetPr
 					Name:      pod.Name,
 				}
 				endpoint, err = toWeightedAddr(podSet.Addresses[podID], s.enableH2Upgrade, s.identityTrustDomain, s.controllerNS)
+				// `Get` doesn't include the namespace in the per-endpoint
+				// metadata, so it needs to be special-cased.
+				endpoint.MetricLabels["namespace"] = pod.Namespace
 				if err != nil {
 					return err
 				}