Upgrade the version of google/errorprone plug-in

This CL upgraded google/errorprone plug-in to 2.3.3 and resolved
some warnings detected from the plug-in.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=238047862

java/google/registry/model/index/EppResourceIndexBucket.java

@@ -30,6 +30,7 @@ import google.registry.model.annotations.VirtualEntity;
 @VirtualEntity
 public class EppResourceIndexBucket extends ImmutableObject {
 
+  @SuppressWarnings("unused")
   @Id
   private long bucketId;