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:

• https://github.com/facebook/jest/pull/5245
• https://github.com/facebook/jest/issues/5119

$ npm ls jest-environment-node

#Broken at v22
+-- [email protected]
| `-- [email protected]
|   `-- [email protected]
|     `-- [email protected]
`-- [email protected]
  `-- [email protected]
    `-- [email protected]
      `-- [email protected]
        `-- [email protected]
		
#Works at v21
+-- [email protected]
| `-- [email protected]
|   `-- [email protected]
|     `-- [email protected]
`-- [email protected]
  `-- [email protected]
    `-- [email protected]
      `-- [email protected]
        `-- [email protected]