[KYUUBI #7292] Add instruction to archive older releases

### Why are the changes needed?

Archive older releases https://www.apache.org/legal/release-policy.html#when-to-archive

Closes #7292

### How was this patch tested?

Not tested

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #7297 from aajisaka/archive-old-releases.

Closes #7292

4cbefd3 [Cheng Pan] nit
677d520 [Cheng Pan] nit
b1f1f67 [Akira Ajisaka] Fix svn delete command example
ef8c575 [Akira Ajisaka] [KYUUBI #7292] Add instruction to archive older releases

Lead-authored-by: Akira Ajisaka <[email protected]>
Co-authored-by: Cheng Pan <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>
(cherry picked from commit 5e23c32)
Signed-off-by: Cheng Pan <[email protected]>

Author: aajisaka

docs/contributing/code/release.md

@@ -278,6 +278,9 @@ Fork and clone [Apache Kyuubi website](https://github.com/apache/kyuubi-website)
 2. Add a new markdown file in `src/zh/release/`, `src/en/release/`
 3. Update `releases` defined in `hugo.toml`'s `[params]` part.
 
+You can use `build/release/pre_gen_release_notes.py` to generate the commit log and the contributor list
+for the release note. Note that the generated lists are only for draft and you still need to edit them.
+
 ### Create an Announcement
 
 Once everything is working, create an announcement on the website and then send an e-mail to the mailing list.
@@ -294,12 +297,29 @@ Remove the deprecated dist repo directories at last.
 
 ```shell
 cd work/svn-dev
-svn delete https://dist.apache.org/repos/dist/dev/kyuubi/{RELEASE_TAG} \
+svn delete https://dist.apache.org/repos/dist/dev/kyuubi/${RELEASE_TAG} \
   --username "${ASF_USERNAME}" \
   --password "${ASF_PASSWORD}" \
   --message "Remove deprecated Apache Kyuubi ${RELEASE_TAG}" 
 ```
 
+## Archive older releases
+
+Remove older releases from [downloads.apache.org](https://downloads.apache.org/). All releases are automatically archived
+and they are still accessible from [archive.apache.org](https://archive.apache.org/dist/).
+
+According to [the ASF release policy](https://www.apache.org/legal/release-policy.html#when-to-archive),
+downloads.apache.org should contain the latest release in each branch that is currently under development.
+
+```shell
+cd work/svn-dev
+export OLD_RELEASE=<release path, e.g. kyuubi-1.10.2>
+svn delete https://dist.apache.org/repos/dist/release/kyuubi/${OLD_RELEASE} \
+  --username "${ASF_USERNAME}" \
+  --password "${ASF_PASSWORD}" \
+  --message "Archive old ${OLD_RELEASE}"
+```
+
 ## Keep other artifacts up-to-date
 
 - Docker Image: https://github.com/apache/kyuubi-docker/blob/master/release/release_guide.md