Add autometrics imports when calling go generate if necessary

[gagbo]

Description

Allows the generator to work around editors automatically removing "unused imports" on save

Checklist

• The CHANGELOG is updated.
• The open-telemetry example in repository works fine:
  • the docker compose file is valid
  • the application compiles and run
  • alerts are getting triggered in Prometheus
• The prometheus example in repository works fine:
  • the docker compose file is valid
  • the application compiles and run
  • alerts are getting triggered in Prometheus
  • exemplars are accessible on the graph