Add working Jest & TypeScript config

- Jest now uses ts-jest for transforms
- TypeScript compilation via `lerna run tsc`

packages/github/__tests__/github.test.js

@@ -1,9 +0,0 @@
-'use strict';
-
-// const github = require('..');
-
-describe('@actions/github', () => {
-  it('needs tests', () => {
-
-  });
-});

packages/github/__tests__/github.test.ts

@@ -0,0 +1,7 @@
+import { github } from '../src/github';
+
+describe('@actions/github', () => {
+  it('needs tests', () => {
+      expect(github()).toBe(true)
+  });
+});