Improve automatic changelog generation

The way how goreleaser generates changelog at the moment includes merge and chore commits.

After each release, maintainers have to manually remove the merge commits.

Our config is:

changelog:
  sort: asc
  filters:
    exclude:
      - "^docs:"
      - "^test:"
      - "^Merge pull request"
      - "^chore"
      - "^Update README.md"

All our options are https://goreleaser.com/customization/changelog/?h=changelog

Since we use conventional commit messages, we know that only limited number of prefixes are allowed: https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/blob/main/docs/developer/commits.md#what-types-can-you-use-for-commit-messages