Swap to using eslint (#435)

* WIP

* ... and more

* yet more...

* and examples (more-or-less) fixed

* Only problematic promisify left...

* Last batch

* rm config header

* Update

* Use Record

* Bumps

packages/util/src/buffer/toU8a.spec.ts

@@ -4,14 +4,14 @@
 
 import { bufferToU8a } from '.';
 
-describe('bufferToU8a', () => {
-  it('returns an empty buffer when null provided', () => {
+describe('bufferToU8a', (): void => {
+  it('returns an empty buffer when null provided', (): void => {
     expect(
       bufferToU8a(null)
     ).toEqual(new Uint8Array([]));
   });
 
-  it('returns a Uint8Buffer with the correct values', () => {
+  it('returns a Uint8Buffer with the correct values', (): void => {
     expect(
       bufferToU8a(Buffer.from([128, 0, 10]))
     ).toEqual(new Uint8Array([128, 0, 10]));