Prepare samples in the package.

Samples/UIWidgetsSamples_2019_4/Assets/.sample.json

+{
+	"displayName":"UIWidgetSample",
+	"description": "Sample to demonstrate the usage of UI Widgets"
+}

add_sample.sh

+#!/usr/bin/env bash
+#set -xeuo pipefail
+#set -x
+
+printf "Preparing samples:\n"
+
+cd com.unity.uiwidgets
+
+mkdir Samples
+cd Samples
+
+cp -r ../../Samples/UIWidgetsSamples_2019_4/Assets UIWidgetsSamples
+
+echo "Finished the sample preparation."