Update README.md

Author: JanSlabon

README.md

@@ -52,6 +52,7 @@ and execute `composer update`. You need to define the `repository` to evaluate t
 By default, this packages depends on a licensed version of the [SetaPDF-Signer](https://www.setasign.com/signer)
 component. If you want to use it with a trial version please use following in your composer.json:
 
+For PHP 7.*:
 ```json
 {
     "require": {
@@ -65,6 +66,20 @@ component. If you want to use it with a trial version please use following in yo
     ]
 }
 ```
+For PHP 8.1:
+```json
+{
+    "require": {
+        "setasign/setapdf-signer-addon-cumulo": "dev-trial-8.1"
+    },
+    "repositories": [
+        {
+            "type": "composer",
+            "url": "https://www.setasign.com/downloads/"
+        }
+    ]
+}
+```
 
 ## License