Update executable-spec SRP

[aniketd]

Description

• Fix the elusive compiler error

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated. If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[teodanciu]

Looks good to me (as much as I can understand), just some minor comments.

It seems like the most significant change is that some types have changed to not use KeyHash but the integer representation thereof, is that about right?

You could squash the commits, since they only make sense together (you wouldn't want to rollback or keep one without the other)

[Lucsanszky]

All looks good apart from what @teodanciu already pointed out.