Add missing extension

composer.json

@@ -23,6 +23,7 @@
     "symfony/options-resolver": "^4.2",
     "symfony/property-access": "^4.3",
     "symfony/serializer": "^4.2",
+    "tritum/form-element-linked-checkbox": "^2.1",
     "typo3/cms-adminpanel": "^10.4",
     "typo3/cms-backend": "^10.4",
     "typo3/cms-belog": "^10.4",

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": "05b3f8c72c31e8ca0d56a0c7bd5a925b",
+    "content-hash": "b1effa48ef2368bfbba63d84c89fa33d",
     "packages": [
         {
             "name": "christophlehmann/imageoptimizer",
@@ -5697,6 +5697,51 @@
             ],
             "time": "2021-07-29T06:20:01+00:00"
         },
+        {
+            "name": "tritum/form-element-linked-checkbox",
+            "version": "2.1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/tritum/form_element_linked_checkbox.git",
+                "reference": "acf3a430b37c6329833af305c011163ece04b45d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/tritum/form_element_linked_checkbox/zipball/acf3a430b37c6329833af305c011163ece04b45d",
+                "reference": "acf3a430b37c6329833af305c011163ece04b45d",
+                "shasum": ""
+            },
+            "require": {
+                "typo3/cms-core": "^9.5.25 || ^10.4.14",
+                "typo3/cms-form": "^9.5.25 || ^10.4.14"
+            },
+            "type": "typo3-cms-extension",
+            "extra": {
+                "typo3/cms": {
+                    "extension-key": "form_element_linked_checkbox"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "TRITUM\\FormElementLinkedCheckbox\\": "Classes/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "GPL-2.0-or-later"
+            ],
+            "authors": [
+                {
+                    "name": "Björn Jacob TRITUM GmbH",
+                    "email": "[email protected]"
+                }
+            ],
+            "support": {
+                "issues": "https://github.com/tritum/form_element_linked_checkbox/issues",
+                "source": "https://github.com/tritum/form_element_linked_checkbox/tree/2.1.2"
+            },
+            "time": "2021-06-01T08:59:34+00:00"
+        },
         {
             "name": "typo3/class-alias-loader",
             "version": "v1.1.3",