build: Updating dependencies

composer:

• mediawiki/mediawiki-codesniffer: 34.0.0 → 35.0.0
• mediawiki/minus-x: 1.1.0 → 1.1.1

npm:

• eslint-config-wikimedia: 0.17.0 → 0.18.1

Additional changes:

• Added the "composer phan" command to conveniently run phan.
• Removing manual extensions for eslint.

Change-Id: I2e668f05bf903f0cf754a3e97476dc4dc2c40e88