Remove examples of composite actions on GitHub

since they are getting to use less in these repositories.
There are no good other examples to replace them with, and they
are not necessary to understand the concept of composite actions.

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Author: tnir

content/actions/tutorials/create-actions/create-a-composite-action.md

@@ -247,11 +247,3 @@ jobs:
         env:
           RANDOM_NUMBER: {% raw %}${{ steps.foo.outputs.random-number }}{% endraw %}
 ```
-
-## Example composite actions on {% data variables.product.github %}
-
-You can find many examples of composite actions on {% data variables.product.github %}.
-
-* [microsoft/action-python](https://github.com/microsoft/action-python)
-* [microsoft/gpt-review](https://github.com/microsoft/gpt-review)
-* [tailscale/github-action](https://github.com/tailscale/github-action)