GH Actions/quicktest: fiddle the PHP versions

Installing on PHP 5.4 with Composer on Windows runs into issues a lot of time. Considering PHP 5.4 is ancient, let's just side-step this problem by using PHP 5.5.

Also see PHPCSStandards/composer-installer 213 for a little more context (yes, I've seen this issue before).

Author: jrfnl

.github/workflows/quicktest.yml

@@ -28,7 +28,18 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'windows-latest']
-        php: ['5.4', '7.2', 'latest']
+        php: ['7.2', 'latest']
+
+        include:
+          - php: '5.4'
+            os: 'ubuntu-latest'
+            custom_ini: false
+          # Installing on Windows with PHP 5.4 runs into all sorts of problems with Composer.
+          # See this issue for more context (yes, I've seen this problem before):
+          # @link https://github.com/PHPCSStandards/composer-installer/pull/213
+          - php: '5.5'
+            os: 'windows-latest'
+            custom_ini: false
 
     name: "QuickTest: PHP ${{ matrix.php }} (${{ matrix.os == 'ubuntu-latest' && 'Linux' || 'Win'  }})"