add php-rrd to requires.

composer.json

@@ -14,11 +14,11 @@
             "Orrisroot\\": "lib/"
         }
     },
-
     "require": {
         "php": ">=7.4.0",
-        "ext-mbstring": "*",
         "ext-json": "*",
+        "ext-mbstring": "*",
+        "ext-rrd": "*",
         "phpmailer/phpmailer": "^6.1",
         "twig/twig": "^3.0"
     },

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "b766d7a4135dc7c7209935b75341a818",
+    "content-hash": "1af7cf1e0057fd467546c12f34cdec69",
     "packages": [
         {
             "name": "phpmailer/phpmailer",
@@ -2124,8 +2124,9 @@
     "prefer-lowest": false,
     "platform": {
         "php": ">=7.4.0",
+        "ext-json": "*",
         "ext-mbstring": "*",
-        "ext-json": "*"
+        "ext-rrd": "*"
     },
     "platform-dev": [],
     "plugin-api-version": "1.1.0"