Update Composer dependencies (2018-10-15)

```
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 0 installs, 2 updates, 0 removals
  - Updating wp-cli/wp-cli dev-master (34ba8d4 => 8dab537):  Checking out 8dab53776b
Writing lock file
Generating autoload files
PHP CodeSniffer Config installed_paths set to ../../phpcompatibility/phpcompatibility-wp/,../../phpcompatibility/php-compatibility/,../../wp-coding-standards/wpcs/
```

Author: wp-make-coffee