"Limit of total fields [1000] in index [github2-pull_raw] has been exceeded" error for "github2:pull"

[ncsibra-lab49]

I'm getting the error mentioned in the title when using "github2:pull" backend.
I'm using the "grimoirelab/grimoirelab:latest" docker image.
The projects.json file contains about 4000 repos and the backend configuration in setup.cfg looks like this:

[github2]
api-token = [...]

[github2:pull]
raw_index = github2-pull_raw
enriched_index = github2-pull_enriched
sleep-for-rate = true
category = pull_request
no-archive = true
studies = [enrich_geolocation:user, enrich_geolocation:assignee, enrich_feelings]

I changed the limit to 2000 with this:

PUT github2-pull_raw/_settings
{
  "index.mapping.total_fields.limit": 2000
}

Elasticsearch documentation mentions that maybe not a good idea: https://www.elastic.co/guide/en/elasticsearch/reference/6.8/mapping.html#mapping-limit-settings

Found a pull request with the same issue, where the structure was changed to avoid this error:
chaoss/grimoirelab-perceval#742

Something similar should be done for "github2" backend or changing the limit is the right solution?