Add version to unsupported header in 1.2 (#7476)

Signed-off-by: kolchfa-aws <[email protected]>

_includes/warning.html

@@ -1 +1 @@
-<p class="unsupported-version-warning">This version of the OpenSearch documentation is no longer maintained. For the latest version, see the <a href="{{ site.url }}/docs{{ page.url }}">current documentation</a>. For information about OpenSearch version maintenance, see <a href="https://opensearch.org/releases.html">Release Schedule and Maintenance Policy</a>.</p>
+<p class="unsupported-version-warning">You're viewing version {{site.opensearch_major_minor_version}} of the OpenSearch documentation. This version is no longer maintained. For the latest version, see the <a href="{{ site.url }}/docs{{ page.url }}">current documentation</a>. For information about OpenSearch version maintenance, see <a href="https://opensearch.org/releases.html">Release Schedule and Maintenance Policy</a>.</p>