Use node assertions as standard solution

ts/features/steps/composition.ts

@@ -1,10 +1,10 @@
 import { When, Then } from '@cucumber/cucumber';
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
 
 When('the step definitions are written in {word}', function (language: string) {
   this.language = language;
 });
 
 Then("I don't get a warning about undefined steps", function () {
-  expect(this.language).to.equal('TypeScript');
+  assert.equal(this.language, 'TypeScript');
 });