Updated to jest version compatible with testMatch

[clexmond]

testMatch is incompatible with jest 18.1.0 and was causing errors thrown when running npm test:

Error: Unknown config option "testMatch" with value "<rootDir>/src/**/__tests__/**/*.js?(x),<rootDir>/src/**/?(*.)(spec|test).js?(x)". This is either a typing error or a user mistake and fixing it will remove this message.

This updates to use 19.0.1 per https://facebook.github.io/jest/docs/configuration.html#testmatch-array-string

Breaking changes between 18.1.0 and 19.0.1 don't affect current tests.

[palafoxernesto]

This pull request fix npm run test error:

PASS src/App.test.js
FAIL scripts/test.js
● Test suite failed to run

SyntaxError: Identifier 'jest' has already been declared

  at Runtime._execModule (node_modules/jest-runtime/build/index.js:442:13)
      at <anonymous>

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been closed, but can be re-opened if further comments indicate that the problem persists. Feel free to tag maintainers if no there is no reply to further comments.