[material-ui][docs] Update the Testing page's Argos link (#41170)

docs/data/material/guides/testing/testing.md

@@ -17,5 +17,5 @@ We don't recommend snapshot testing though.
 ## Internal
 
 We have **a wide range** of tests for Material UI so we can
-iterate with confidence on the components, for instance, the visual regression tests provided by [Argos-CI](https://app.argos-ci.com/mui/material-ui) have proven to be really helpful.
+iterate with confidence on the components, for instance, the visual regression tests provided by [Argos](https://argos-ci.com) have proven to be really helpful.
 To learn more about the internal tests, you can have a look at the [README](https://github.com/mui/material-ui/blob/HEAD/test/README.md).