🔧 QA: lint PHP files in this repo

Author: jrfnl

.travis.yml

@@ -54,6 +54,9 @@ before_install:
 
 
 script:
+  # Lint PHP files against parse errors.
+  - composer lint
+
   # Validate the composer.json file on low/high PHP versions.
   # @link https://getcomposer.org/doc/03-cli.md#validate
   - composer validate --no-check-all --strict