Test with PHP 5.4 and 8.4 too

Author: micheh

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: ['7.4']
+        php-versions: ['5.4', '7.4', '8.4']
         dependencies:
           - lowest
           - highest