Introduce "Snapshot" section to changelog (#39)

CHANGELOG.md

@@ -1,5 +1,22 @@
 # CHANGELOG
 
+### Snapshot
+_Not yet released in a stable build_
+
+Introduce `SdkIntDeferredColor`, a `DeferredColor` implementation that delegates to different `DeferredColor` sources
+depending on the Android OS runtime version.
+
+Add a few extension functions for accessibility to the view extensions library, including `setContentDescription`.
+
+Use AppCompat to improve DeferredColor and DeferredDrawable implementations on Android OS versions < 23. In particular,
+default DeferredColor implementations can resolve attribute-backed color selectors, and default DeferredDrawable
+implementations can resolve vector drawables and tints correctly.
+
+Compile with Kotlin 1.4.10 and publish the source code in
+[explicit mode](https://kotlinlang.org/docs/reference/whatsnew14.html#explicit-api-mode-for-library-authors).
+
+Target Android SDK 30.
+
 ## 1.0.0
 _2020-07-29_