Add espresso changelog

Author: gilles-duboscq

.gitattributes

@@ -1,2 +1,3 @@
 /truffle/CHANGELOG.md merge=union
-/sdk/CHANGELOG.md merge=union
+/sdk/CHANGELOG.md merge=union
+/espresso/CHANGELOG.md merge=union

espresso/CHANGELOG.md

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+# Espresso Changelog
+
+## Version 21.3.0
+### User-visible changes
+* Java 17 guest and host support.
+* Support using interop buffer-like object as a `byte[]` in espresso.
+* Add buffer interop messages to the explicit interop API.
+* The Polyglot API is not enabled by default anymore. When needed, contexts should be created with the `java.Polyglot` option set to `true`.
+* The HotSwapAPI is not auto-enabled by debugging anymore. When needed, contexts should be created with the `java.HotSwapAPI` option set to `true`.
+* Avoid illegal reflective access warnings with host Java >= 11.
+### Internal changes
+* The Static Object Model has moved to Truffle.
+* On-Stack-Replacement using the new Truffle bytecode OSR API.
+* Detect and report trivial methods.
+* Enable saturated type flows.
+### Noteworthy fixes
+* Performance and functional related to JDWP.
+* Fix some crashes observed when using the JNA.