Incorrect generated/beats/fields.ecs.yml, not accounting on top_level: false

[aleksmaus]

Description of the issue:

We are using the following file as a source of ECS mappings for osquery_manager integration:
https://github.com/elastic/ecs/blob/main/generated/beats/fields.ecs.yml

It does have as field at the the top level there, which causes our integration validation to fail for 3.0.0 format spec.

As far as I understand generated file should not include as field at the top level because it is marked with top_level: false attribute.

ecs/generated/ecs/ecs_nested.yml

Line 157 in 969aeba

top_level: false

Currently it has

and not additional information for us of the field is a top level or not

[aleksmaus]

Same issue with other fields, here is the list

	"as",
	"code_signature",
	"elf",
	"macho",
	"pe",
	"risk",
	"x509",