BREAKING CHANGE: resolve gRPC API proxy targets (machines) on server instead of client, needs upgrade to v0.20 (#247)

Co-authored-by: Pasha Sviderski <me@psviderski.name>

test/e2e/service_test.go

@@ -1300,7 +1300,7 @@ myapp.example.com {
 
 		for _, mi := range machineImages {
 			// Checking only DockerImages because the machines in ucind cluster don't use the containerd image store.
-			if !machinesWithContainers.Contains(mi.Metadata.Machine) {
+			if !machinesWithContainers.Contains(mi.Metadata.MachineId) {
 				// This is the machine without service containers, it should not have the unique image.
 				for _, img := range mi.Images {
 					assert.NotContains(t, img.RepoTags, uniqueImage)
@@ -1317,7 +1317,7 @@ myapp.example.com {
 				}
 			}
 			assert.True(t, hasImage, "Machine %s with container should have image %s",
-				mi.Metadata.Machine, uniqueImage)
+				mi.Metadata.MachineId, uniqueImage)
 		}
 	})