chore(docs): inline OIDC flow diagram (#12255)

goodtune · web-flow · commit 7a245e61b16d · 2024-02-26T04:48:01.000Z
When viewing the Authentication page, the diagram showing the flow is a useful
resource for understanding the rest of the page.

Rather than linking to a specific version of the SVG, inline it as part of the
documentation.
diff --git a/docs/admin/auth.md b/docs/admin/auth.md
@@ -1,6 +1,6 @@
 # Authentication
 
-[OIDC with Coder Sequence Diagram](https://raw.githubusercontent.com/coder/coder/138ee55abb3635cb2f3d12661f8caef2ca9d0961/docs/images/oidc-sequence-diagram.svg).
+![OIDC with Coder Sequence Diagram](../images/oidc-sequence-diagram.svg).
 
 By default, Coder is accessible via password authentication. Coder does not
 recommend using password authentication in production, and recommends using an
