add deprecation notice for Subversion (#34143)

Co-authored-by: Steve Guntrip <12534592+stevecat@users.noreply.github.com>

content/authentication/securing-your-account-with-two-factor-authentication-2fa/accessing-github-using-two-factor-authentication.md

@@ -96,6 +96,8 @@ Enabling 2FA doesn't change how you authenticate to {% data variables.product.pr
 
 ## Using two-factor authentication to access a repository using Subversion
 
+{% data reusables.subversion.sunset %}
+
 When you access a repository via Subversion, you must provide a {% data variables.product.pat_generic %} instead of entering your password. For more information, see "[Creating a {% data variables.product.pat_generic %}](/github/authenticating-to-github/creating-a-personal-access-token)."
 
 ## Troubleshooting

content/get-started/getting-started-with-git/about-remote-repositories.md

@@ -88,6 +88,8 @@ You can also install {% data variables.product.prodname_cli %} to use {% data va
 {% ifversion not ghae %}
 ## Cloning with Subversion
 
+{% data reusables.subversion.sunset %}
+
 You can also use a [Subversion](https://subversion.apache.org/) client to access any repository on {% data variables.product.prodname_dotcom %}. Subversion offers a different feature set than Git. For more information, see "[What are the differences between Subversion and Git?](/github/importing-your-projects-to-github/what-are-the-differences-between-subversion-and-git)"
 
 You can also access repositories on {% data variables.product.prodname_dotcom %} from Subversion clients. For more information, see "[Support for Subversion clients](/github/importing-your-projects-to-github/support-for-subversion-clients)."

content/get-started/importing-your-projects-to-github/working-with-subversion-on-github/subversion-properties-supported-by-github.md

@@ -11,6 +11,8 @@ versions:
   ghec: '*'
 shortTitle: Properties supported by GitHub
 ---
+{% data reusables.subversion.sunset %}
+
 ## Executable files (`svn:executable`)
 
 We convert `svn:executable` properties by updating the file mode directly before adding it to the Git repository.

content/get-started/importing-your-projects-to-github/working-with-subversion-on-github/support-for-subversion-clients.md

@@ -13,6 +13,8 @@ shortTitle: Support for Subversion clients
 ---
 GitHub supports Subversion clients via the HTTPS protocol. We use a Subversion bridge to communicate svn commands to GitHub.
 
+{% data reusables.subversion.sunset %}
+
 ## Supported Subversion features on GitHub
 
 ### Checkout

content/get-started/importing-your-projects-to-github/working-with-subversion-on-github/what-are-the-differences-between-subversion-and-git.md

@@ -62,6 +62,8 @@ SVN is configured to assume that the history of a project never changes. Git all
 
 {% endtip %}
 
+{% data reusables.subversion.sunset %}
+
 ## Further reading
 
 - "[Subversion properties supported by GitHub](/articles/subversion-properties-supported-by-github)"

data/reusables/subversion/sunset.md

@@ -0,0 +1,9 @@
+{% note %}
+
+**Note**: Subversion support will be removed from {% data variables.product.prodname_dotcom %}
+on January 8, 2024. A future release of {% data variables.product.prodname_ghe_server %} after January 8, 2024 
+will also remove Subversion support. To read more about this, see [the GitHub blog][svn-sunset-blog].
+
+[svn-sunset-blog]: https://github.blog/2023-01-20-sunsetting-subversion-support/
+
+{% endnote %}