Added lint target as php-cs-fixer only returns a non-zero exit code during dry run now

.travis.yml

@@ -11,4 +11,5 @@ install:
     - travis_retry composer install --no-interaction --prefer-source
 
 script:
-    - make all
+    - make lint
+    - make test

Makefile

@@ -1,12 +1,15 @@
 THIS := $(realpath $(lastword $(MAKEFILE_LIST)))
 HERE := $(shell dirname $(THIS))
 
-.PHONY: all fix test
+.PHONY: all fix lint test
 
-all: fix test
+all: lint test
 
 fix:
 	php $(HERE)/vendor/bin/php-cs-fixer fix --config=$(HERE)/.php_cs
 
+lint:
+	php $(HERE)/vendor/bin/php-cs-fixer fix --config=$(HERE)/.php_cs --dry-run
+
 test:
 	php $(HERE)/vendor/bin/phpunit --configuration $(HERE)/phpunit.xml