deprecate v2 (#195)

Signed-off-by: rulex123 <erica.manno@gmail.com>

Author: rulex123

cache/src/main/java/io/envoyproxy/controlplane/cache/v2/SimpleCache.java

@@ -2,6 +2,7 @@
 
 import io.envoyproxy.controlplane.cache.NodeGroup;
 
+@Deprecated
 public class SimpleCache<T> extends io.envoyproxy.controlplane.cache.SimpleCache<T, Snapshot> {
   public SimpleCache(NodeGroup<T> nodeGroup) {
     super(nodeGroup);

cache/src/main/java/io/envoyproxy/controlplane/cache/v2/Snapshot.java

@@ -25,6 +25,7 @@
  * {@code Snapshot} is a data class that contains an internally consistent snapshot of v2 xDS
  * resources. Snapshots should have distinct versions per node group.
  */
+@Deprecated
 @AutoValue
 public abstract class Snapshot extends io.envoyproxy.controlplane.cache.Snapshot {
 

server/src/main/java/io/envoyproxy/controlplane/server/V2DiscoveryServer.java

@@ -20,6 +20,7 @@
 import java.util.Collections;
 import java.util.List;
 
+@Deprecated
 public class V2DiscoveryServer extends DiscoveryServer<DiscoveryRequest, DiscoveryResponse> {
 
   public V2DiscoveryServer(ConfigWatcher configWatcher) {