Merge pull request #103 from wp-cli/update/wp-cli-2-12

Require `wp-cli/wp-cli` v2.12

Author: mrsdizzie

composer.json

@@ -12,7 +12,7 @@
  }
  ],
  "require": {
- "wp-cli/wp-cli": "^2.5"
+ "wp-cli/wp-cli": "^2.12"
  },
  "require-dev": {
  "wp-cli/entity-command": "^1.3 || ^2",