docs: specify 1.12.0+ent incompat with nomad (#12883)
docs: specify 1.12.0+ent incompat with nomad (#12883)

Due to build changes in Consul 1.12.0 the `+ent` modifier is missing
from the version reported by `/v1/agent/self`.

Nomad looks for the `ent` modifier when determining whether to reconcile
services in non-default namespaces. Without the modifier Nomad will only
end up removing services from the default Consul namespace.
hashicorp/consul,hashicorp/consul,hashicorp/consul,hashicorp/consul