docs(release): update RELEASE.md (#4832)

* Update RELEASE.md

* Screenshot of commit status check for release

* Update RELEASE.md

* Update RELEASE.md

* Update RELEASE.md

Co-authored-by: Yuan (Bob) Gong <gongyuan94@gmail.com>

RELEASE.md

@@ -93,13 +93,15 @@ if you only want to use or contribute to this repo.
 * OS: Linux (MacOS not supported yet due to different behavior of sed)
 * Permissions needed
     * Can create a branch in github.com/kubeflow/pipelines.
+    * (Before [#4840](https://github.com/kubeflow/pipelines/issues/4840) is resolved) one would need the admin access to kubeflow/pipelines repo.
     * Can trigger cloudbuild jobs in ml-pipeline-test GCP project.
 * Tools that should be in your `$PATH`
     * jq 1.6 https://stedolan.github.io/jq/download/
     * yq https://github.com/mikefarah/yq/releases/tag/3.3.0
     * jdk 8
     * node 12
-    * bazel 0.24.0
+    * bazel 0.24.0 https://github.com/bazelbuild/bazel/releases/tag/0.24.0
+    * python 3 (on linux, one would need the `python` to be `python3` by default instead of `python2`)
 * Preparations
     1. Clone github.com/kubeflow/pipelines repo into `$KFP_REPO`.
     2. `cd $KFP_REPO`
@@ -168,6 +170,10 @@ Do the following things before a release:
 
 1. Verify cloudbuild and postsubmit tests are passing: visit https://github.com/kubeflow/pipelines/commits/master for master branch.
 
+![How to very cloudbuild and postsubmit status](release-status-check.png)
+
+If not, contact the KFP team to determine if the failure(s) would block the release.
+
 ### Releasing from release branch
 
 Note, when releasing from master, all the below mentions of "release branch" means master branch.
@@ -181,6 +187,11 @@ Note, when releasing from master, all the below mentions of "release branch" mea
     * ...
     Contact @Bobgy if you are not sure what next version should be.
 
+1. Verify all the required tools are installed properly:
+    ```bash
+    ./hack/check-release-needed-tools.sh
+    ```
+
 1. Update all version refs in release branch by
     ```bash
     ./hack/release.sh $VERSION $BRANCH
@@ -191,6 +202,7 @@ Note, when releasing from master, all the below mentions of "release branch" mea
 
 1. View related cloudbuild jobs' statuses by clicking the latest commit's status icon
 in the release branch. The page will look like https://github.com/kubeflow/pipelines/runs/775788343.
+Refer to the above screenshot to find the page.
 
 1. Wait and make sure the `build-each-commit` cloudbuild job that builds all images
 in gcr.io/ml-pipeline-test succeeded. If it fails, please click "View more details
@@ -216,20 +228,20 @@ and then "Retry", because after waiting for previous step, artifacts are now rea
 1. Release `kfp` python packages to PyPI.
     ```bash
     pip3 install twine --user
-    gsutil cp gs://ml-pipeline/release/$TAG_NAME/kfp.tar.gz kfp-$TAG_NAME.tar.gz
-    python3 -m twine upload --username kubeflow-pipelines kfp-$TAG_NAME.tar.gz
+    gsutil cp gs://ml-pipeline/release/$VERSION/kfp.tar.gz kfp-$VERSION.tar.gz
+    python3 -m twine upload --username kubeflow-pipelines kfp-$VERSION.tar.gz
     ```
 
     !!! The file name must contain the version. See https://github.com/kubeflow/pipelines/issues/1292
 
-1. Create a GitHub release using `$TAG_NAME` git tag and title `Version $TAG_NAME`,
+1. Create a GitHub release using `$VERSION` git tag and title `Version $VERSION`,
 fill in the description. Detailed steps:
    
    1. [Draft a new release](https://github.com/kubeflow/pipelines/releases/new).
-   1. Typing in version tag field to search and select the "$TAG_NAME" tag published in release instructions above.
+   1. Typing in version tag field to search and select the "$VERSION" tag published in release instructions above.
    Its format is like `X.Y.Z` or `X.Y.Z-rc.N`.
 
-   1. Use this template for public releases and replace the `$TAG_NAME` with real values.
+   1. Use this template for public releases and replace the `$VERSION` with real values.
        <pre>
        To deploy Kubeflow Pipelines in an existing cluster, follow the instruction in [here](https://www.kubeflow.org/docs/pipelines/standalone-deployment-gcp/) or via UI [here](https://console.cloud.google.com/ai-platform/pipelines)
 
@@ -238,7 +250,7 @@ fill in the description. Detailed steps:
        python3 -m pip install kfp kfp-server-api --upgrade
        ```
 
-       See the [Change Log](https://github.com/kubeflow/pipelines/blob/$TAG_NAME/CHANGELOG.md)
+       See the [Change Log](https://github.com/kubeflow/pipelines/blob/$VERSION/CHANGELOG.md)
        </pre>
 
        Use this template for prereleases (release candidates) and **PLEASE CHECK** the
@@ -251,22 +263,21 @@ fill in the description. Detailed steps:
        python3 -m pip install kfp kfp-server-api --pre --upgrade
        ```
 
-       See the [Change Log](https://github.com/kubeflow/pipelines/blob/$TAG_NAME/CHANGELOG.md)
+       See the [Change Log](https://github.com/kubeflow/pipelines/blob/$VERSION/CHANGELOG.md)
        </pre>
 
-1. Update master branch to the same version.
+1. Update master branch to the same version and include latest changelog:
     ```bash
-    export TAG_NAME=<TAG_NAME>
     git checkout master
     git pull
     git checkout -b <your-branch-name>
     # This avoids line break at end of line.
-    echo -n $TAG_NAME > VERSION
+    echo -n $VERSION > VERSION
     # This takes a while.
     ./hack/release-imp.sh
-    git checkout $TAG_NAME -- CHANGELOG.md
+    git checkout $VERSION -- CHANGELOG.md
     git add -A
-    git commit -m "chore(release): bump version to $TAG_NAME on master branch"
+    git commit -m "chore(release): bump version to $VERSION on master branch"
     ```
 
 1. If current release is not a prerelease, create a PR to update version in kubeflow documentation website: