HBASE-22823 Mark Canary as Public/Evolving

Signed-off-by: Xu Cang <[email protected]>

Author: Caroline Zhou

hbase-server/src/main/java/org/apache/hadoop/hbase/tool/Canary.java

@@ -109,7 +109,7 @@
  * 3. zookeeper mode - for each zookeeper instance, selects a zNode and
  * outputs some information about failure or latency.
  */
-@InterfaceAudience.Private
+@InterfaceAudience.Public
 public final class Canary implements Tool {
   // Sink interface used by the canary to outputs information
   public interface Sink {