Allow composer files to be PHP version specific

- need to support multiple composer entries to support
  both PHP 5.4 and PHP7.4

.github/workflows/continuous-integration.yml

@@ -16,17 +16,17 @@ jobs:
         # Define jobs for all combinations of php, mariadb and extension, up to "include"
         # Tests will be performed for each combination
         # These can fail if "experimental" is true. Currently all must pass
-        php-version: ["7.4"]
         mariadb-version: ["10.3"]
         extension: ["pdo_mysql"]
         experimental: [false]
         include:
-          # Define jobs for individual combinations to be tested
-          # These can fail if "experimental" is true. Currently all can fail
-          - php-version: "8.0"
-            mariadb-version: "10.3"
-            extension: "pdo_mysql"
-            experimental: true
+          - php-version: 5.4
+            composer-json: "composer.json"
+            composer-lock: "composer.lock"
+          #- php-version: 7.4
+          #  composer-json: ""
+          #  composer-lock: ""
+
 
     services:
       mariadb: