Site: Add instructions to consult/update the JIRA release dashboard

Close apache#2963

site/_docs/howto.md

@@ -713,6 +713,9 @@ Note: release artifacts (dist.apache.org and repository.apache.org) are managed
 
 Before you start:
 
+* Consult the [release dashboard](https://issues.apache.org/jira/secure/Dashboard.jspa?selectPageId=12333950) to get a
+ quick overview about the state of the release and take appropriate actions in order to resolve pending tickets or
+ move them to another release/backlog.
 * Send an email to [dev@calcite.apache.org](mailto:dev@calcite.apache.org) notifying that RC build process
   is starting and therefore `main` branch is in code freeze until further notice.
 * Set up signing keys as described above.
@@ -981,7 +984,9 @@ with a change comment
 (fill in release number and date appropriately).
 Uncheck "Send mail for this update". Under the [releases tab](https://issues.apache.org/jira/projects/CALCITE?selectedItem=com.atlassian.jira.jira-projects-plugin%3Arelease-page&status=released-unreleased)
 of the Calcite project mark the release X.Y.Z as released. If it does not already exist create also
-a new version (e.g., X.Y+1.Z) for the next release.
+a new version (e.g., X.Y+1.Z) for the next release. In order to make the [release dashboard](https://issues.apache.org/jira/secure/Dashboard.jspa?selectPageId=12333950)
+reflect state of the next release, change the fixVersion in the [JIRA filter powering the dashboard](https://issues.apache.org/jira/issues/?filter=12346388)
+and save the changes.
 
 After 24 hours, announce the release by sending an email to
 [announce@apache.org](https://mail-archives.apache.org/mod_mbox/www-announce/) using an `@apache.org`