fix: update tooltip docs to show react popper instead of thetter

Author: dornelasnelson

src/components/Tooltip/docs/Tooltip.mdx

@@ -50,7 +50,7 @@ Use the tooltip for user on-boarding, guiding information about a new feature, d
 It is possible to adjust the position of the tooltip connection to the target with the `placement` prop. Below is a list
 of possible options which are represented in the square next to it. It is important to keep in mind that the tooltip
 will be moved to a different position if it cannot be shown on the desired side due to screen sizes. Read more about the
-Tether library [here](http://tether.io).
+Popper library [here](https://popper.js.org/).
 
 <TooltipPlacementExample />