Upgrade chai to 4.3.4

[Voileexperiments]

https://github.com/chaijs/chai/releases/tag/v4.3.4

4.3.4 finally fixed BigInt display in should assertions, which is currently a critical issue with every JS kata that use BigInts in test assertions because this would be displayed when tests with them fail:

const chai = require("chai");
const assert = chai.assert;
chai.config.truncateThreshold = 0;

describe("example tests", function() {
  it("returns correct values for example N", function() {
    assert.deepEqual([1n, 2n], [3n, 4n], "Failed when n = 3");
  }); 
});

[hobovsky]

There's a known workaround, and it was planned to be documented but I never got to this: codewars/docs#257

But now, since it got fixed in Chai itself, it's even better.

[kazk]

Updated in JavaScript Node 12 and TypeScript 4.2.