add CHANGES.md with summary of changes in the recent releases

Author: morgwai

CHANGES.md

@@ -0,0 +1,12 @@
+# Summaries of visible changes between releases
+
+### 5.2
+- `TaskTrackingExecutor`: add convenience `tryEnforceTermination(...)` method.
+- `Awaitable`: `awaitMultiple(...)`: ensure operations do not block after an interrupt, clear interrupt status when throwing an `AwaitInterruptedException`.
+
+### 5.1
+- `TaskTrackingThreadPoolExecutor`: add constructor(poolSize, threadFactory).
+
+### 5.0
+- `CallableTaskExecution`: `run()`: also pass `Error`s thrown by `call()` to `completeExceptionally(e)`.
+- `TaskTrackingExecutor`: remove deprecated `decorateRejectedExecutionHandler(executor)` static helper.

README.md

@@ -6,6 +6,8 @@ Copyright 2021 Piotr Morgwai Kotarbinski, Licensed under the Apache License, Ver
 **latest release: [5.1](https://search.maven.org/artifact/pl.morgwai.base/java-utils/5.1/jar)**
 ([javadoc](https://javadoc.io/doc/pl.morgwai.base/java-utils/5.1))
 
+See [CHANGES](CHANGES.md) for the summary of changes between releases. If the major version of a subsequent release remains unchanged, it is supposed to be backwards compatible in terms of API and behaviour with previous ones with the same major version (meaning that it should be safe to just blindly update in dependent projects and things should not break under normal circumstances).
+
 **Note:** from version 2.0, `java.util.logging` utilities have been moved to a separate [repo](https://github.com/morgwai/jul-utils).
 
 ## MAIN USER CLASSES