Replace GitHub with data variable (#36757)

Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>

Author: jsoref

data/reusables/actions/actions-billing.md

@@ -1,3 +1,3 @@
-{% data variables.product.prodname_actions %} usage is free for standard {% data variables.product.prodname_dotcom %}-hosted runners in public repositories, and for self-hosted runners. For a list of standard GitHub-hosted runners available for public repositories, see [AUTOTITLE](/actions/writing-workflows/choosing-where-your-workflow-runs/choosing-the-runner-for-a-job#standard-github-hosted-runners-for-public-repositories)
+{% data variables.product.prodname_actions %} usage is free for standard {% data variables.product.prodname_dotcom %}-hosted runners in public repositories, and for self-hosted runners. See [AUTOTITLE](/actions/writing-workflows/choosing-where-your-workflow-runs/choosing-the-runner-for-a-job#standard-github-hosted-runners-for-public-repositories).
 
 For private repositories, each {% data variables.product.prodname_dotcom %} account receives a certain amount of free minutes and storage for use with {% data variables.product.prodname_dotcom %}-hosted runners, depending on the account's plan. Any usage beyond the included amounts is controlled by spending limits.