For clarity: how long are confidential data preserved

[larsvilhuber]

Suggestion:

After https://github.com/social-science-data-editors/template_README/blob/42894e3a09ce85ee4faafd790cf55467bca18307/template-README.md?plain=1#L25 add

• [ ] Confidential data used in this paper and not provided as part of the public replication package will be preserved for ___ years after publication, in accordance with journal policies.

[larsvilhuber]

Moved it to later in the README.