obsolete PHP 5.5, test with PHP 7.2

PHP 5.5 is not supported by upstream anymore and hence removed from the
list of supported versions.

As I already use PHP 7.2 for some internal projects, we might run tests
of CDN Linker with it as well. Please keep in mind 7.2 is still a RC,
RC6 as of the time I am writing this.

.gitlab-ci.yml

@@ -3,17 +3,13 @@
   before_script:
   - composer install -n --dev
   script:
-  -  bin/atoum -f test.php
+  - bin/atoum -f test.php
   cache:
     key: "$CI_BUILD_STAGE"
     paths:
     - bin
     - vendor
 
-unittest_with_php_5.5:
-  <<: *howto_unit_test
-  image: blitznote/ci-php:5.5
-
 unittest_with_php_5.6:
   <<: *howto_unit_test
   image: blitznote/ci-php:5.6
@@ -25,4 +21,8 @@ unittest_with_php_7.0:
 unittest_with_php_7.1:
   <<: *howto_unit_test
   image: blitznote/ci-php:7.1
+
+unittest_with_php_7.2:
+  <<: *howto_unit_test
+  image: blitznote/ci-php:7.2
   allow_failure: true

README.rst

@@ -19,7 +19,7 @@ CDN Linker for Wordpress and Magento
   CDN,links,cloudfront,simplecdn,media,performance,distribution,accelerator,content,speed,cloud
 
 *Requirements*
-  Wordpress 2.7 – 4.x, PHP ≥ 5.3 or HHVM ≥ 3.3.0
+  Wordpress 2.7 – 4.x, PHP ≥5.6 or HHVM ≥ .3.0
 
 Rewrites links to static files to your own CDN network.
 
@@ -122,11 +122,7 @@ Troubleshooting
 Disqus
   Either uncheck `rewrite root-relative refs` or add `count.js` and `embed.js` to `exclude if substring`.
 
-Livefyre, IntenseDebate, and Juvia
-  No issues.
-
 HHVM
-  Please note issue `1854 <//github.com/facebook/hhvm/issues/1854>`_.
   For CDN Linker’s *post-processing* feature you will have to install `hhvm-zmq <//github.com/duxet/hhvm-zmq>`_
   (monitor issue `1214 <//github.com/facebook/hhvm/issues/1214>`_) or resort to Redis.