docs: update network config v1 document url

The current latest version of the cloud-init upstream
document URL has changed. Added the latest known good
version for the URL.

Change-Id: Ia2d48bea644a4d78fdf79792451a2f1d4c389f96
Signed-off-by: Adrian Vladu <avladu@cloudbasesolutions.com>

doc/source/services.rst

@@ -141,7 +141,7 @@ Capabilities:
     * hostname
     * public keys
     * static network configuration (Debian and `network config v1
-      <https://cloudinit.readthedocs.io/en/latest/topics/network-config-format-v1.html>`_
+      <https://cloudinit.readthedocs.io/en/22.4.2/topics/network-config-format-v1.html>`__
       formats)
     * user data