fix: add ipywidgets in requirements and badge to README

Author: lostmygithubaccount

README.md

@@ -1,5 +1,7 @@
 # Ibis Example Notebooks
 
+[![Build and Test](https://github.com/ibis-project/ibis-examples/actions/workflows/ci.yml/badge.svg)](https://github.com/ibis-project/ibis-examples/actions/workflows/ci.yml?query=branch%3Amain)
+
 This repository contains runnable example notebooks for
 [Ibis](ibis-project.org/). They are intended to be educational and give users
 examples of common Ibis workflows.

requirements.txt

@@ -1,5 +1,6 @@
 notebook
 jupyterlab == 3.4.8
+ipywidgets
 altair
 ibis-framework[sqlite,duckdb,clickhouse]
 ibis-substrait