Add ecs fields in container logs

[MichaelKatsoulis]

What does this PR do?

This PR adds ecs fields in container_logs data stream of kubernetes integrations.
Without the declaration of those fields the mappings where taking default types which is not optimal in all cases.
An example is the message field which as a default was mapped to keyword instead of text. (https://elastic.slack.com/archives/CJZ9U5G9X/p1635183286042600)

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• If I'm introducing a new feature, I have modified the Kibana version constraint in my package's manifest.yml file to point to the latest Elastic stack release (e.g. ^7.13.0).

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)

[elasticmachine]

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• Start Time: 2021-10-27T10:56:25.850+0000

• Duration: 31 min 0 sec

• Commit: 973ed1e

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🤖 GitHub comments

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[MichaelKatsoulis]

/test

[ChrsMark]

lgtm, apart of the conflicts :).
Btw will we change the type of the message to text too here or in another PR?

[MichaelKatsoulis]

lgtm, apart of the conflicts :).
Btw will we change the type of the message to text too here or in another PR?

- external: ecs
   name: message

message is an ecs fields which type is text (https://github.com/elastic/ecs/blob/master/schemas/base.yml#L52)

[ChrsMark]

Ok, so we are just fine with https://github.com/elastic/integrations/pull/2033/files#diff-737e87b60df2c6af40cd83068b0b27dbec3c5145b13cc060d3522531595e2fefR18. Gotcha.