travis.yml: workaround for travis-ci/travis-ci#7124

dg · dg · commit 714afb64d0da · 2017-01-16T13:30:14.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -4,6 +4,7 @@ php:
     - 7.0
     - 7.1
 
+env:
 matrix:
     include:
         - php: 7.0
