Update DB migrations in book (#6611)

* Update DB migrations in book

* Merge branch 'unstable' into db-migrations-v22

Author: michaelsproul

book/src/database-migrations.md

@@ -16,6 +16,7 @@ validator client or the slasher**.
 
 | Lighthouse version | Release date | Schema version | Downgrade available? |
 |--------------------|--------------|----------------|----------------------|
+| v6.0.0             | Nov 2024     | v22            | no                   |
 | v5.3.0             | Aug 2024     | v21            | yes                  |
 | v5.2.0             | Jun 2024     | v19            | no                   |
 | v5.1.0             | Mar 2024     | v19            | no                   |
@@ -208,6 +209,7 @@ Here are the steps to prune historic states:
 
 | Lighthouse version | Release date | Schema version | Downgrade available?                |
 |--------------------|--------------|----------------|-------------------------------------|
+| v6.0.0             | Nov 2024     | v22            | no                                  |
 | v5.3.0             | Aug 2024     | v21            | yes                                 |
 | v5.2.0             | Jun 2024     | v19            | yes before Deneb using <= v5.2.1    |
 | v5.1.0             | Mar 2024     | v19            | yes before Deneb using <= v5.2.1    |