Simplify build set up

.travis.yml

@@ -7,23 +7,16 @@ sudo: false
 cache:
   directories:
     - $HOME/.composer/cache/files
-
-php:
- - 5.6
-
-env:
-  matrix:
-    - PHPUNIT_TEST=1
-    - PHPCS_TEST=1
-
 matrix:
   include:
-    - php: 5.6
+    - php: 7.1
       env: PHPUNIT_TEST=1
-    - php: 7.0
-      env: PHPUNIT_TEST=1
-    - php: 7.1.2
+    - php: 7.2
       env: PHPUNIT_TEST=1
+    - php: 7.3
+      env: PHPUNIT_TEST=1 PHPCS_TEST=1
+
+
 
 before_script:
   - export PATH=~/.composer/vendor/bin:$PATH