Provide a way for users to specify validUntil when making document updates

[varjas]

When updating a document the "validUntil" field in the corresponding history.json file is prefilled with "to-be-determined" which causes checks on the PR to fail. Additional work is needed to manually update the value.

This process could be smoothed out if users could specify the "validUntil" field in the contribution tool user interface so PRs are ready to merge without any other changes. If possible, it would be even easier if the generated PR automatically selected and included that information from the corresponding Issue.

Original suggestion: OpenTermsArchive/contrib-declarations#3815 (comment)

[MattiSG]

Thanks @varjas for reporting! The automatic inclusion was broken and brought back in #181 👏
Let's see in which other cases such as feature would be used now that it's back 🙂

[MattiSG]

Seeing OpenTermsArchive/contrib-declarations#3846, OpenTermsArchive/contrib-declarations#3847 and OpenTermsArchive/contrib-declarations#3848, it seems that #181 fixed the problem, and I will proceed to close this issue. Please comment / reopen if the feature seems relevant again!