ICU-22722 Update README.md

[srl295]

updates to README.md for legal purposes

• late 2024 (16.0) updates .github#17

Checklist

• Required: Issue filed: https://unicode-org.atlassian.net/browse/ICU-22722
• Required: The PR title must be prefixed with a JIRA Issue number.
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number.
• Issue accepted (done by Technical Committee after discussion)

[markusicu]

Changes lgtm.
It might be easier/faster to use the per-release standing ticket for minor doc fixes -- ICU-22722 -- rather than ask the TC for permission to accept the new ticket.

[jira-pull-request-webhook]

Hooray! The files in the branch are the same across the force-push. 😃

~ Your Friendly Jira-GitHub PR Checker Bot