Tighten era bounds of Conway specific API to ConwayEraOnwards

[newhoggy]

Changelog

- description: |
    Constraint the following functions to `ConwayEraOnwards`:
    - createProposalProcedure
    - createVotingProcedure
    - eraDecodeVotingCredential
    - fromGovernanceAction
    - fromProposalProcedure
    - makeGoveranceActionId
    - toGovernanceAction
    - toVoterRole
    - toVotingCredential
  type:
    - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  # - improvement    # QoL changes e.g. refactoring
  # - bugfix         # fixes a defect
  # - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - documentation  # change in code docs, haddocks...

Context

Those functions and data types were constrained to ShelleyBasedEra previously, but that's too lose for something that's applicable to only Conway onwards.

Those functions are now constrained to ConwayEraOnwards instead.

Constraining to ConwayEraOnwards tightly allows the CLI parser to integrate with it in a type-safe way. This type-safety is what controls the visibility of CLI commands and options based on whether the era is Conway onwards.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• The change log section in the PR description has been filled in
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-8.10.7 and ghc-9.2.7
• The changelog section in the PR is updated to describe the change
• Self-reviewed the diff

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[Jimbo4350]

This needs to wait till after we have made sufficient progress in the cli.

Re-request review

[github-actions]

This PR is stale because it has been open 45 days with no activity.