Implement New Action Keyword Flick (#370)

* Implement New Action Keyword `Flick`

* Revise the location of the flick keyword

* Update Documentation

Author: joshuariveramnltech

AppiumLibrary/keywords/_touch.py

@@ -192,6 +192,17 @@ def drag_and_drop(self):
         """TO BE IMPLEMENTED
         Refer to : appium.webdriver.extensions.action_helpers"""
 
-    def flick(self):
-        """TO BE IMPLEMENTED
-        Refer to : appium.webdriver.extensions.action_helpers"""
+    def flick(self, start_x:int, start_y:int, end_x:int, end_y:int):
+        """Flick from one point to another point.
+
+        Args:
+        - ``start_x`` - x-coordinate at which to start
+        - ``start_y`` - y-coordinate at which to start
+        - ``end_x``   - x-coordinate at which to stop
+        - ``end_y``   - y-coordinate at which to stop
+
+        Usage:
+        | Flick | 100 | 100 | 100 | 400 | # Flicks the screen up. |
+        """
+        driver = self._current_application()
+        driver.flick(start_x, start_y, end_x, end_y)