Fix build github workflow reference (#2843)

## PR Summary
This small PR fixes the build github workflow reference in
`tests/README.md`.

---------

Signed-off-by: Emmanuel Ferdman <[email protected]>

Author: emmanuel-ferdman

tests/README.md

@@ -10,9 +10,9 @@ accessing the webpage with a real browser and can access the state of the page
 so behavior can be asserted.
 
 The [Static Server Service](https://webdriver.io/docs/static-server-service/) is
-used mainly in the [CI](../github/workflows/build.yml) to serve the book on port
-`localhost:8080` such that the test runner can access it. This mode is used when
-`npm start` or `npm test` is executed.
+used mainly in the [CI](../.github/workflows/build.yml) to serve the book on
+port `localhost:8080` such that the test runner can access it. This mode is used
+when `npm start` or `npm test` is executed.
 
 > **Tip:** Use `cargo xtask web-tests` to run the tests in this directory from
 > anywhere in the repository.