PATCH: Update Deprecation Policy

[mrshll1001]

Following the decision of the Stewardship Committee on 2025-06-17, this PATCH updates the deprecation policy in the standard documentation to read as the following:

If a term, such as a field title (known as a class or property in JSON schema) is scheduled to be renamed or removed as a result of the revision process, the next release must deprecate the term within the schema. The following MAJOR release must rename or remove the term from the schema, making it obsolete. Data that is published may use deprecated terms, but will receive warnings from the 360Giving Data Quality tool. Once obsolete, terms in published data will be treated like any other non-Standard fields.

[mrshll1001]

Just noting that I have run a docs build and everything appears to be fine:

• Deprecation Policy section on the update-deprecation-policy branch of the docs

[mariongalley]

Approving but could we uppercase the T on Data Quality Tool?

[mrshll1001]

Good catch, I've fixed that. It's reflected on the docs build as well, so I'll proceed with the merge now.