docs: OEP-1: Add a section on announcing changes

Previously, OEP-1 didn't have a clear process for announcing merges,
which is especially important for OEP updates that didn't necessarily
go through a wider review.

Addresses issue #493

oeps/processes/oep-0001.rst

@@ -223,6 +223,9 @@ The Open edX community is given the opportunity to comment on the OEP.
 The Arbiter serves to keep the discussion on track and to bring the review
 process to a final resolution.
 
+Finally, please follow the `After Merging`_ guidelines once your change has been
+merged.
+
 .. _Announcements - Architecture category: https://discuss.openedx.org/c/announcements/architecture
 .. _#open-edx-proposals Slack channel: https://openedx.slack.com/messages/C1L370YTZ/details/
 
@@ -564,9 +567,28 @@ changes made, and a link to the pull request where the discussion and approval
 took place. The changes should be ordered such that the most recent change is
 at the top of the list.
 
+After Merging
+*************
+
+After merging a pull request - whether it was the addition of a new OEP, a
+wording/status change to an existing OEP, or the addition of a new ADR to an
+OEP - please announce the change:
+
+#. Announce the merge - and briefly describe the change - in the
+   `#open-edx-proposals Slack channel`_.
+#. If applicable, announce to an appropriate working group in Slack or an
+   upcoming meeting.
+#. If applicable, close the associated GitHub ticket(s) associated with the
+   change.
+
 Change History
 **************
 
+2024-06-25
+==========
+* Add a section on announcing changes
+* `Pull request #602 <https://github.com/openedx/open-edx-proposals/pull/602>`_
+
 2024-06-25
 ==========
 * Remove "Withdrawn" status