chore: bump dashboard vsn to e1.3.0-beta.6

Makefile

@@ -16,7 +16,7 @@ endif
 # Dashboard version
 # from https://github.com/emqx/emqx-dashboard5
 export EMQX_DASHBOARD_VERSION ?= v1.4.1
-export EMQX_EE_DASHBOARD_VERSION ?= e1.2.1
+export EMQX_EE_DASHBOARD_VERSION ?= e1.3.0-beta.6
 
 # `:=` should be used here, otherwise the `$(shell ...)` will be executed every time when the variable is used
 # In make 4.4+, for backward-compatibility the value from the original environment is used.