Add missing environment variable

RemiCollin · RemiCollin · commit fd2659546a3e · 2018-02-09T13:13:35.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -9,6 +9,7 @@ php:
 env:
   global:
     - DRIVER_VERSION="stable"
+    - ADAPTER_VERSION="^1.0.0"
 
 sudo: false
 
