test: bump up jest to v27 that introduces new defaults (#315)

The jest-circus is now default runner, no need to depend on it explicitly.
The testEnvironment also changed its default to "node".
Also types/jest is now needless, we can use jest/globals instead.
https://jestjs.io/blog/2021/05/25/jest-27

__tests__/main.test.ts

@@ -2,6 +2,7 @@ import {wait} from '../src/wait'
 import * as process from 'process'
 import * as cp from 'child_process'
 import * as path from 'path'
+import {expect, test} from '@jest/globals'
 
 test('throws invalid number', async () => {
   const input = parseInt('foo', 10)

jest.config.js

@@ -1,9 +1,7 @@
 module.exports = {
   clearMocks: true,
   moduleFileExtensions: ['js', 'ts'],
-  testEnvironment: 'node',
   testMatch: ['**/*.test.ts'],
-  testRunner: 'jest-circus/runner',
   transform: {
     '^.+\\.ts$': 'ts-jest'
   },

package.json

@@ -28,18 +28,16 @@
     "@actions/core": "^1.2.6"
   },
   "devDependencies": {
-    "@types/jest": "^26.0.15",
     "@types/node": "^14.14.9",
     "@typescript-eslint/parser": "^4.8.1",
     "@vercel/ncc": "^0.25.1",
     "eslint": "^7.17.0",
     "eslint-plugin-github": "^4.1.1",
     "eslint-plugin-jest": "^24.1.3",
-    "jest": "^26.6.3",
-    "jest-circus": "^26.6.3",
+    "jest": "^27.0.6",
     "js-yaml": "^3.14.0",
     "prettier": "2.2.1",
-    "ts-jest": "^26.4.4",
+    "ts-jest": "^27.0.3",
     "typescript": "^4.1.3"
   }
 }