feat: TS v4, tslint -> eslint, add cspell support (#240)

Update all dependencies, migrate from tslint (deprecated) to typescript-eslint, and add support for
cspell.

BREAKING CHANGE: migrated from tslint (deprecated) to eslint.

src/lib/hash.spec.ts

@@ -1,11 +1,11 @@
-// tslint:disable:no-expression-statement no-object-mutation
 import test from 'ava';
+
 import { sha256, sha256Native } from './hash';
 
 test(
   'sha256',
-  (t, input: string, expected: string) => {
-    t.is(sha256(input), expected);
+  async (t, input: string, expected: string) => {
+    t.is(await sha256(input), expected);
     t.is(sha256Native(input), expected);
   },
   'test',