Update Composer dependencies 2019-01-30

- Updating wp-cli/shell-command (v2.0.1 => v2.0.2)
- Updating gettext/gettext (v4.6.1 => v4.6.2)
- Updating mck89/peast (v1.8.1 => v1.9.1)
- Updating justinrainbow/json-schema (5.2.7 => 5.2.8)
- Updating composer/xdebug-handler (1.3.1 => 1.3.2)
- Updating composer/ca-bundle (1.1.3 => 1.1.4)
- Updating composer/composer (1.8.0 => 1.8.2)
- Updating squizlabs/php_codesniffer (3.3.2 => 3.4.0)

Author: schlessera