Test against PHP 7.1 on AppVeyor

Author: WyriHaximus

appveyor.yml

@@ -3,16 +3,22 @@ platform:
   - x64
 clone_folder: c:\projects\php-project-workspace
 
-
 ## Build matrix for lowest and highest possible targets
 environment:
   matrix:
   - dependencies: lowest
     php_ver_target: 7.0
+  - dependencies: lowest
+    php_ver_target: 7.1
   - dependencies: current
     php_ver_target: 7.0
+  - dependencies: current
+    php_ver_target: 7.1
   - dependencies: highest
     php_ver_target: 7.0
+  - dependencies: highest
+    php_ver_target: 7.1
+
 ## Cache composer bits
 cache:
     - '%LOCALAPPDATA%\Composer\files -> composer.lock'