add gradle 6.8.3

fdroidserver/gradlew-fdroid

@@ -145,6 +145,7 @@ get_sha() {
         '6.8')    echo 'e2774e6fb77c43657decde25542dea710aafd78c4022d19b196e7e78d79d8c6c' ;;
         '6.8.1')  echo 'fd591a34af7385730970399f473afabdb8b28d57fd97d6625c388d090039d6fd' ;;
         '6.8.2')  echo '8de6efc274ab52332a9c820366dd5cf5fc9d35ec7078fd70c8ec6913431ee610' ;;
+        '6.8.3')  echo '7faa7198769f872826c8ef4f1450f839ec27f0b4d5d1e51bade63667cbccd205' ;;
         *) exit 1
     esac
 }