Upgrade 'standard' from 13.x to 14.x

[abetomo]

• Upgrade other packages as well.
• Drop support Node.js 6
  • Follow 'standard'. https://github.com/standard/standard/blob/master/package.json#L36-L38

[zeke]

Thanks! I released this as a new major version.

~/git/zeke/standard-markdown master
$ np major


Warning: No files field specified in package.json nor is a .npmignore file present. Having one of those will prevent you from accidentally publishing development-specific files along with your package's source code to npm.


Publish a new version of standard-markdown (current: 5.1.0)

Commits:
- Merge pull request #36 from abetomo/upgrade_packages  3328e7d
- Drop support Node.js 6  6e3ee69
- Upgrade 'standard' from 13.x to 14.x  aa9c801

Commit Range:
v5.1.0...master


  ✔ Prerequisite check
  ✔ Git
  ✔ Cleanup
  ✔ Installing dependencies using npm
  ✔ Running tests using npm
  ✔ Bumping version using npm
  ✔ Publishing package using npm
  ✔ Pushing tags
  ✔ Creating release draft on GitHub

 standard-markdown 6.0.0 published 🎉