Bump php and phpunit dependency to 7.1 and 7.0 respectively

Author: luispabon

composer.json

@@ -12,8 +12,8 @@
         }
     ],
     "require": {
-        "php": ">=7.0",
-        "phpunit/phpunit": "^6.0"
+        "php": ">=7.1",
+        "phpunit/phpunit": "^7.0"
     },
     "autoload": {
         "psr-4": {
@@ -27,7 +27,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.0-dev"
+            "dev-master": "3.0-dev"
         }
     }
 }