Introduce php_version_main and make php_version always format x.y

tasks/main.yml

@@ -9,4 +9,4 @@
 
   - debug: msg='We have to implement some Drupal site specific configuration here'
 
-  when: '"drupalconsole" not in excluded_roles and php_version|default("5.5") != "5.3"'
+  when: '"drupalconsole" not in excluded_roles and php_version_main|default("7") != "7"'