chore(master): release contracts 2.6.0

[github-actions[bot]]

:robot: I have created a release beep boop

2.6.0 (2023-05-08)

Features

• contract-upgrade: update contract metadata (26ca5c6)

---

This PR was generated with Release Please. See documentation.

[github-actions[bot]]

:robot: Release is at https://github.com/fairDataSociety/fdp-contracts/releases/tag/fdp-contracts-main-v2.6.0 :sunflower: