The following is an error.
```
path.js:39
    throw new ERR_INVALID_ARG_TYPE('path', 'string', path);
    ^

TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received type undefined
    at assertPath (path.js:39:11)
    at Object.resolve (path.js:1090:7)
    at Command.<anonymous> (/home/vagrant/work/standard-markdown/cli.js:34:28)
    at Command.listener (/home/vagrant/work/standard-markdown/node_modules/commander/index.js:315:8)
    at Command.emit (events.js:182:13)
    at Command.parseArgs (/home/vagrant/work/standard-markdown/node_modules/commander/index.js:665:12)
    at Command.parse (/home/vagrant/work/standard-markdown/node_modules/commander/index.js:474:21)
    at Object.<anonymous> (/home/vagrant/work/standard-markdown/cli.js:42:4)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
```

https://github.com/nodejs/Release#release-schedule

Fix as cli failed

Update CI test to LTS version

I upgraded the package and
fixed it according to the latest 'standard' rules.

Modify to follow the rules of the new 'standard'