Add support for ephemeral mark

[wata727]

The ephemeral mark is introduced in Terraform v1.10. This change allows policies to use expr.ephemeral as well as expr.sensitive.

deny_non_ephemeral_password contains issue if {
	providers := terraform.providers({"password": "string"}, {})
	password := providers[_].config.password

	password.ephemeral == false

	issue := tflint.issue("password should be ephemeral", password.range)
}

TFLint v0.55+ is required to support ephemeral values, below that the ephemeral will always be false.