Deprecate PipeStepPair.

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/generic/PipeStepPair.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2021 DiffPlug
+ * Copyright 2020-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,10 @@
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
+/**
+ * @deprecated use FenceStep instead
+ */
+@Deprecated
 public class PipeStepPair {
 	/** The two steps will be named {@code <name>In} and {@code <name>Out}. */
 	public static Builder named(String name) {