Upgrade to Jest v21

[bengwall]

This will be a little work because the Jest CLI was re-written with v21 which just recently came out. The runCLI options appear to have been changed and there is little documentation that I can see.

[alexb-uk]

I don't appear to have any issues running Jest v21 but when I try to upgrade to v22 I get the following error:

$ jest
 FAIL  functions\example.test.js
  ● Test suite failed to run

    TypeError: environment.setup is not a function

      at node_modules/jest-runner/build/run_test.js:112:23

After a Google search I'm guessing this is to do with "serverless-jest-plugin" needing to upgrade.

See:

• Added Jest Environment on top of the test file jestjs/jest#5245
• @jest-environment node not working in v22 jestjs/jest#5119

$ npm ls jest-environment-node

#Broken at v22
+-- jest@22.0.4
| `-- jest-cli@22.0.4
|   `-- jest-config@22.0.4
|     `-- jest-environment-node@22.0.4
`-- serverless-jest-plugin@0.1.6
  `-- jest@19.0.2
    `-- jest-cli@19.0.2
      `-- jest-config@19.0.4
        `-- jest-environment-node@19.0.2
		
#Works at v21
+-- jest@21.2.1
| `-- jest-cli@21.2.1
|   `-- jest-config@21.2.1
|     `-- jest-environment-node@21.2.1
`-- serverless-jest-plugin@0.1.6
  `-- jest@19.0.2
    `-- jest-cli@19.0.2
      `-- jest-config@19.0.4
        `-- jest-environment-node@19.0.2