Add changelog

CHANGELOG.md

@@ -0,0 +1,13 @@
+# Changelog
+
+## `v0.5.0`
+
+- `Picker::new` has been deprecated; use `PickerOptions`.
+- Improved interactive checks: now requires both stdin and stdout to be interactive.
+- Various keybinding changes.
+- Better exposure of nucleo internals:
+  - Restart the internal matcher with `Picker::restart`
+  - Update internal configuration without rebuilding the `Picker` using `Picker::update_config`
+  - Modify the default query string using `Picker::update_query`
+- New `PickerOptions` for more flexible `Picker` configuration:
+  - Specifying an initial query string with `PickerOptions::query`