Update data-encoding to 0.6

Context

Fixes a small bug, so we want it in 14.0~rc1.

Corresponding MR on tezos/opam-repository: opam-repository!339 (merged)

Manually testing the MR

If the CI succeeds, that should be enough. Have a look at the list of packages which are upgraded in opam-repository!339 (merged) though, to check that we don't upgrade dangerous libs.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR