Add 7.2.1 landing page

R1/source/releases/rel7.2.1.rst

+.. _rel7.2.1:
+
+Varnish Cache 7.2.1
+===================
+
+* Source download `varnish-7.2.1.tgz </downloads/varnish-7.2.1.tgz>`_
+
+* SHA256=4d937d1720a8ec19c533f972d9303a1c9889b7bfca7437893ae5c27cf204a940
+
+Varnish Cache 7.2.1 is a security fix release of 7.2, related to the two
+VSVs :ref:`VSV00010` and :ref:`VSV00011`. All users should, as soon as
+possible, upgrade to a secure version.
+
+More information:
+
+* List of most important `Changes in 7.2 <https://varnish-cache.org/docs/7.2/whats-new/changes-7.2.html>`_
+* Help on `Upgrading to Varnish 7.2 <https://varnish-cache.org/docs/7.2/whats-new/upgrading-7.2.html>`_
+* `Full changes.rst entry for 7.2.1 <https://github.com/varnishcache/varnish-cache/blob/7.2/doc/changes.rst#varnish-cache-721-2022-11-08>`_
+
+For installation instructions including information about cloud images see
+`the Varnish Installation Manual </docs/trunk/installation/index.html>`_
+
+We recommend using the manual installation procedure available at:
+https://packagecloud.io/varnishcache/varnish72/install#manual