Fixing 'command not found' error: Step 4 (#106)

* fixing path file

* Update .github/steps/4-personalize-codespace.md

Co-authored-by: Shinsuke Higashiyama aka Cinzeng Zia <94058150+sinsukehlab@users.noreply.github.com>

---------

Co-authored-by: Hector Alfaro <hectorsector@github.com>
Co-authored-by: Shinsuke Higashiyama aka Cinzeng Zia <94058150+sinsukehlab@users.noreply.github.com>

Author: 3 people

.github/steps/4-personalize-codespace.md

@@ -45,7 +45,7 @@ Let's see how this works!
 
    sudo apt-get update
    sudo apt-get install sl
-   export PATH=$PATH:/usr/games
+   echo "export PATH=\$PATH:/usr/games" >> ~/.bashrc
    ```
 
 1. Save the file.