Bump ouroboros-consensus to ^>=2.0 for cardano-node 10.7.2

[Jimbo4350]

Changelog

- description: |
    Bump ouroboros-consensus dependency to ^>=2.0 for cardano-node 10.7.2 release
  type:
   - release
  projects:
   - cardano-api

Context

Bumps ouroboros-consensus dependency bound from ^>=1.0 to ^>=2.0 on the cardano-api-10.25.0.0 release branch, required for cardano-node 10.7.2.

How to trust this PR

Single line change in cardano-api.cabal — dependency bound bump only, no code changes.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• Self-reviewed the diff