Updated Gecko driver to version 1.4.0

Author: budtmo

Appium/Dockerfile

@@ -150,7 +150,7 @@ USER 1300:1301
 ENV APPIUM_DRIVER_ESPRESSO_VERSION="3.5.0"
 ENV APPIUM_DRIVER_FLUTTER_VERSION="2.9.2"
 ENV APPIUM_DRIVER_FLUTTER_INTEGRATION_VERSION="1.1.3"
-ENV APPIUM_DRIVER_GECKO_VERSION="1.3.9"
+ENV APPIUM_DRIVER_GECKO_VERSION="1.4.0"
 ENV APPIUM_DRIVER_UIAUTOMATOR2_VERSION="3.7.6"
 RUN appium driver install --source=npm appium-espresso-driver@${APPIUM_DRIVER_ESPRESSO_VERSION} && \
     appium driver install --source=npm appium-flutter-driver@${APPIUM_DRIVER_FLUTTER_VERSION} && \