Don't allow Pagerfanta < 1.1.0

The reason for this is that older versions of Pagerfanta still (incorrectly) use the option previous_message rather than prev_message in the Default template (whiteoctober/Pagerfanta#230), but this branch now uses prev_message everywhere.
In order to keep the two in-step, we need to ensure that this code is running against Pagerfanta >= 1.1.0

composer.json

@@ -12,7 +12,7 @@
     ],
     "require": {
         "php": ">=5.3",
-        "pagerfanta/pagerfanta": "^1.0.0|^2.0.0",
+        "pagerfanta/pagerfanta": "^1.1.0|^2.0.0",
         "symfony/framework-bundle": "~2.3|~3.0|~4.0",
         "symfony/property-access": "~2.3|~3.0|~4.0",
         "symfony/twig-bundle": "~2.3|~3.0|~4.0"