Update outdated link in first_3d_game's going_further.rst (godotengine#9163)

* Update outdated link in first_3d_game's going_further.rst

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Co-authored-by: Max Hilbrunner <[email protected]>
Co-authored-by: Matthew <[email protected]>

Author: 3 people

getting_started/first_3d_game/going_further.rst

@@ -17,7 +17,7 @@ Where should you begin? Below, you'll find a few pages to start exploring and
 build upon what you've learned so far.
 
 But before that, here's a link to download a completed version of the project:
-`<https://github.com/godotengine/godot-3d-dodge-the-creeps>`_.
+`<https://github.com/godotengine/godot-demo-projects/releases>`_.
 
 Exploring the manual
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