GH Actions: exclude PHP 5.4-Windows combi everywhere

This was in part already done in 663 and 677, but there was still one PHP 5.4-Windows build being run.

This last one is now also excluded.

Author: jrfnl

.github/workflows/test.yml

@@ -92,6 +92,11 @@ jobs:
         php: ['5.4', '5.5', '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5']
         custom_ini: [false]
 
+        exclude:
+          # Installing on Windows with PHP 5.4 runs into all sorts of problems (which are not ours).
+          - php: '5.4'
+            os: 'windows-latest'
+
         include:
           # Skip test runs on builds which are also run in the coverage job.
           # Note: the tests on PHP 7.2 will still be run as the coverage build uses custom_ini settings for that version.