Fix: update for Nextflow v2 parser's strict syntax requirements - #73

Changes

• Use resourceLimits instead of check_max()
• Do not declare groovy variables in config files
• Move workflow.onComplete handler inside default workflow

Issues

fixes #72

PR Checklist

(Strikethrough any points that are not applicable.)

• This comment contains a description of changes with justifications, with any relevant issues linked.
• [ ] Write unit tests for any new features, bug fixes, or other code changes. testing framework not yet implemented
• [ ] Update docs if there are any API changes. on hold until before public release
• [ ] If a new nextflow process is implemented, define the process container and stub.
• Update CHANGELOG.md with a short description of any user-facing changes and reference the PR number. Guidelines: https://keepachangelog.com/en/1.1.0/