Add ANONYMOUS SASL mechanism

* Start by bumping RMQ / Erlang on Windows GHA runners

Author: lukebakken

.ci/windows/versions.json

@@ -1,4 +1,4 @@
 {
-  "erlang": "26.2.5.2",
-  "rabbitmq": "4.0.0-beta.5"
+  "erlang": "27.0.1",
+  "rabbitmq": "4.0.0-beta.6"
 }