update kirby to v5 and add refresh cache panel view button

public/site/plugins/refresh-cache-button/composer.json

@@ -0,0 +1,21 @@
+{
+    "name": "adrienpayet/refresh-cache-button",
+    "description": "A panel view buttons that allows to refresh the project or projects cache.",
+    "license": "MIT",
+    "type": "kirby-plugin",
+    "version": "1.0.0",
+    "authors": [
+        {
+            "name": "Adrien Payet",
+            "email": "adrien@studio-variable.com"
+        }
+    ],
+    "require": {
+        "getkirby/composer-installer": "^1.1"
+    },
+    "config": {
+        "allow-plugins": {
+            "getkirby/composer-installer": true
+        }
+    }
+}