Square brackets around description

src/freedombone-utils-android

                 { echo '    {';
                   echo "      \"name\": \"${app_name}\",";
                   echo "      \"short_description\": \"$SHORT_DESCRIPTION\",";
-                  echo "      \"description\": \"$DESCRIPTION\",";
+                  echo "      \"description\": [";
+                  echo "        \"$DESCRIPTION\"";
+                  echo '      ],';
                   echo "      \"icon_url\": \"/icons/${app_name}.png\",";
                   echo "      \"clients\": ["; } >> "$plinth_api"