Fix Travis & Scrutinizer build (#106)

Author: Slamdunk

.scrutinizer.yml

@@ -0,0 +1,4 @@
+build:
+    environment:
+        variables:
+            COMPOSER_ROOT_VERSION: '1.8.0'

.travis.yml

@@ -2,6 +2,10 @@ language: php
 
 sudo: false
 
+env:
+  global:
+    - COMPOSER_ROOT_VERSION=1.8.0
+
 php:
   - '7.1'
   - '7.2'