L3 - Default Description
Context:
As Elasticsearch 7.14 & 7.15 got release we should add it to the supported versions.
AT:
- Elasticsearch 7.14 & 7.15 is added to supported versions
- the supported environment docs are updated
- the integration test pipeline has a stage for Elastic 7.14 & 7.15
- the support of 7.14 & 7.15 is mentioned in the support announcements https://docs.camunda.org/enterprise/announcement/