Deprecate Hystrix instrumentation

Hystrix is no longer in active development, and is currently
in maintenance mode, see:
https://github.com/Netflix/Hystrix#hystrix-status

You can migrate to Resilience4j which has Micrometer support, see:
https://github.com/resilience4j/resilience4j/tree/master/resilience4j-micrometer

Closes gh-4587

Author: jonatan-ivanov

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/hystrix/HystrixMetricsBinder.java

@@ -26,8 +26,13 @@
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.binder.MeterBinder;
 
+/**
+ * @deprecated since 1.13.0, Hystrix is no longer in active development, and is currently
+ * in maintenance mode.
+ */
 @NonNullApi
 @NonNullFields
+@Deprecated
 public class HystrixMetricsBinder implements MeterBinder {
 
     @Override

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/hystrix/MicrometerMetricsPublisher.java

@@ -25,10 +25,13 @@
 import io.micrometer.core.instrument.MeterRegistry;
 
 /**
+ * @deprecated since 1.13.0, Hystrix is no longer in active development, and is currently
+ * in maintenance mode.
  * @author Clint Checketts
  */
 @NonNullApi
 @NonNullFields
+@Deprecated
 public class MicrometerMetricsPublisher extends HystrixMetricsPublisher {
 
     private final MeterRegistry registry;

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/hystrix/MicrometerMetricsPublisherCommand.java

@@ -30,10 +30,13 @@
 import java.util.concurrent.TimeUnit;
 
 /**
+ * @deprecated since 1.13.0, Hystrix is no longer in active development, and is currently
+ * in maintenance mode.
  * @author Clint Checketts
  */
 @NonNullApi
 @NonNullFields
+@Deprecated
 public class MicrometerMetricsPublisherCommand implements HystrixMetricsPublisherCommand {
 
     private static final InternalLogger LOG = InternalLoggerFactory

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/hystrix/MicrometerMetricsPublisherThreadPool.java

@@ -26,10 +26,13 @@
 /**
  * Micrometer publisher for Hystrix thread pool metrics.
  *
+ * @deprecated since 1.13.0, Hystrix is no longer in active development, and is currently
+ * in maintenance mode.
  * @since 1.2.0
  */
 @NonNullApi
 @NonNullFields
+@Deprecated
 public class MicrometerMetricsPublisherThreadPool implements HystrixMetricsPublisherThreadPool {
 
     private static final String NAME_HYSTRIX_THREADPOOL = "hystrix.threadpool";

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/hystrix/package-info.java

@@ -15,6 +15,8 @@
  */
 
 /**
- * Meter binders for Hystrix.
+ * Meter binders for Hystrix. Deprecated since 1.13.0, Hystrix is no longer in active
+ * development, and is currently in maintenance mode.
  */
+@Deprecated
 package io.micrometer.core.instrument.binder.hystrix;