Set specific PHP version

Author: acoburn

appveyor.yml

@@ -8,7 +8,7 @@ init:
     - SET COMPOSER_NO_INTERACTION=1
 
 install:
-    - cinst -y php
+    - cinst php --version 7.0.9
     - cd c:\tools\php71
     - copy php.ini-production php.ini
     - echo date.timezone="UTC" >> php.ini