Update warning requirement from 2.x to 4.x

[dependabot-preview]

Updates the requirements on warning to permit the latest version.

Release notes

Sourced from warning's releases.

v4.0.2

• chore: add contributing guidlines (6cc6c6e)
• chore(CHANGELOG): fix header (b7dbf8c)
• chore(commit): add commitlint config (98d8121)
• chore(commitlint.config): remove scope case rule (3b1da02)
• chore(CONTRIBUTING.md): add npm script to commit (8bda7d0)
• chore(package.json): add commit script (ae2e9a1)
• chore(package): add commitizen and git commit msg linter (76b1329)
• chore(package): update dependencies (3c4213b)
• chore(release): v4.0.2 (e480622)
• docs(CHANGELOG): v4.0.2 (33425d8)
• docs(readme): add Greenkeeper badge (c9aa6ec)
• fix: remove providesModule annotation (1d808f1)
• fix(use jest instead of tap): tap is a PITA to debug (c4c026b)
• ci(travis.yml): add travisbuddy hook (3dc3f84)
• ci(travis.yml): remove node_modules from cache (4e4007f)
• ci(travis): add custom npm install script/lock updater (2dfa8b0)

Changelog

Sourced from warning's changelog.

4.0.2 (2018-08-17)

Bug Fixes

• use jest instead of tap: tap is a PITA to debug (c4c026b)
• remove [provides](https://github.com/provides)Module annotation (1d808f1)

Change Log

All notable changes to this project will be documented in this file.
See Conventional Commits for commit guidelines.

4.0.1 (2018-05-30)

Bug Fixes

• add var printWarning = to comply with ES5 strict mode (677dcfa), closes #25

4.0.0 (2018-05-22)

Bug Fixes

• Remove "browser" version (521f5f5), closes #18 /github-redirect.dependabot.com/facebook/fbjs/pull/86#issuecomment-285204734
• Update warning to use the latest version from facebook/fbjs (0572ddd)

Chores

• LICENSE: Change from BSD modified to MIT (5a63a1b)

BREAKING CHANGES

• LICENSE: Change License to MIT from BSD+patents
• This changes the internal workings. A major release is
  made to ensure minimal effect on downstream users.

3.0.0 (2015-10-04)

BREAKING CHANGE

... (truncated)

Commits

• See full diff in compare view

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[coveralls]

Coverage remained the same at 85.827% when pulling 9037606 on dependabot/npm_and_yarn/warning-4.x into 4a5220c on master.