Updates to alpha releases of dependencies

To ensure compatibility with PSR-15-dependent packages, or those with
PHP 7.1+ updates.

- zendframework/zend-expressive-helpers: `^5.0.0alpha1 || ^5.0`
- zendframework/zend-expressive-router: `^3.0.0alpha1 || ^3.0`
- zendframework/zend-expressive-template: `^2.0.0alpha1 || ^2.0`

Author: weierophinney

composer.json

@@ -23,9 +23,9 @@
         "php": "^7.1",
         "psr/container": "^1.0",
         "psr/http-message": "^1.0.1",
-        "zendframework/zend-expressive-helpers": "^5.0.0-dev",
-        "zendframework/zend-expressive-router": "^3.0.0-dev",
-        "zendframework/zend-expressive-template": "^2.0.0-dev",
+        "zendframework/zend-expressive-helpers": "^5.0.0alpha1 || ^5.0",
+        "zendframework/zend-expressive-router": "^3.0.0alpha1 || ^3.0",
+        "zendframework/zend-expressive-template": "^2.0.0alpha1 || ^2.0",
         "zendframework/zend-servicemanager": "^2.7.8 || ^3.3",
         "zendframework/zend-view": "^2.8.1"
     },