Improve CI
Created by: GernotMaier
Improve CI.
Functional changes:
- use current branch for parameter file validation (this is important: this means that any changes to schema files applied in the current branch are used in the validation; otherwise these workflows would fail)
- add yaml linter to schema validation
- add a 'sticky pull request' comment - meaning that when pressing 'pull request ready for review', a checklist appears for the reviewer (easier to remember than adding instructions to the README file; see this example)
Code improvements from discussions with @orelgueta and linters:
- separate schema and parameter file validation
- make shellcheck happier (especially the fragile for loops