Add Ansible community 8.0.0rc1 porting guide (#80873)

docs/docsite/rst/porting_guides/porting_guide_8.rst

@@ -94,6 +94,18 @@ Networking
 
 No notable changes
 
+Porting Guide for v8.0.0rc1
+===========================
+
+Known Issues
+------------
+
+community.docker
+~~~~~~~~~~~~~~~~
+
+- docker_api connection plugin - does **not work with TCP TLS sockets**! This is caused by the inability to send an ``close_notify`` TLS alert without closing the connection with Python's ``SSLSocket`` (https://github.com/ansible-collections/community.docker/issues/605, https://github.com/ansible-collections/community.docker/pull/621).
+- docker_container_exec - does **not work with TCP TLS sockets** when the ``stdin`` option is used! This is caused by the inability to send an ``close_notify`` TLS alert without closing the connection with Python's ``SSLSocket`` (https://github.com/ansible-collections/community.docker/issues/605, https://github.com/ansible-collections/community.docker/pull/621).
+
 Porting Guide for v8.0.0b1
 ==========================