Update release docs

Signed-off-by: Yi Chen <github@chenyicn.net>

docs/release.md

@@ -52,27 +52,38 @@ If you want to push changes to the `release-X.Y` release branch, you have to che
 
 ### Create GitHub tag
 
-1. After the above PR is merged, rebase your release branch and push new tag to upstream:
+1. After the above PR is merged, rebase your release branch:
 
     ```bash
     git fetch upstream
     git rebase upstream/release-X.Y
     ```
 
+2. Modify `VERSION` file in the root directory of the project:
+
     - For the RC tag as follows:
 
     ```bash
-    git tag vX.Y.Z-rc.N
-    git push upstream vX.Y.Z-rc.N
+    vX.Y.Z-rc.N
     ```
 
     - For the official release tag as follows:
 
     ```bash
-    git tag vX.Y.Z
-    git push upstream vX.Y.Z
+    vX.Y.Z
+    ```
+
+3. Commit the changes:
+
+    ```bash
+    VERSION=$(cat VERSION)
+    git add VERSION
+    git commit -s -m "Release $VERSION"
+    git push
     ```
 
+4. Submit a PR to the release branch. After the PR is merged, a new tag will be automatically created if the `VERSION` file has changed.
+
 ### Release Spark Operator Image
 
 After a pre-release/release tag is pushed, a release workflow will be triggered to build and push Spark operator docker image to Docker Hub.
@@ -87,7 +98,7 @@ After the draft release is published, a release workflow will be triggered to up
 
 ## Update Changelog
 
-Update the Changelog by running:
+Update the `CHANGELOG.md` file by running:
 
 ```bash
 python hack/generate-changelog.py \