ci: Add config.json

Test support for Moodle 5.0 onwards.

Author: dlmsr

.github/workflows/config.json

@@ -0,0 +1,20 @@
+{
+  "moodle-plugin-ci": "4.5.9",
+  "main-moodle": "MOODLE_500_STABLE",
+  "main-php": "8.4",
+  "main-db": "pgsql",
+  "moodle-testmatrix": {
+    "MOODLE_500_STABLE": {
+      "php": ["8.2", "8.3", "8.4"],
+      "db": ["pgsql", "mariadb", "mysqli"]
+    },
+    "MOODLE_501_STABLE": {
+      "php": ["8.2", "8.3", "8.4"],
+      "db": ["pgsql", "mariadb", "mysqli"]
+    },
+    "main": {
+      "php": ["8.3", "8.4"],
+      "db": ["pgsql", "mariadb", "mysqli"]
+    }
+  }
+}