docs: Add information about new release tool.

Add docs about the version bump script.

Signed-off-by: Jose Carlos Venegas Munoz <jose.carlos.venegas.munoz@intel.com>

release/README.md

@@ -2,20 +2,49 @@
 
 This directory contains tools for Kata Containers releases.
 
+## update-repository-version.sh ##
+
+This script creates a GitHub pull request (a.k.a PR) to change the version in
+all the Kata repositories.
+
+For more information on using the script, run the following:
+
+```bash
+$ ./update-repository-version.sh -h
+```
+
+### Update Kata projects to a new version ###
+Kata Containers is divided into multiple projects. With each release, all
+project versions are updated to keep the version consistent.
+
+To update all versions for all projects, use the following:
+
+```bash
+$ make bump-kata-version NEW_VERSION=<new-version>
+```
+
+The makefile target bump-kata-version creates a GitHub pull request in the Kata
+repositories. These pull requests are tested by the Kata CI to ensure the
+entire project is working prior to the release. Next, the PR is approved and
+merged by Kata Containers members.
+
 ## tag_repos.sh ##
 
+After all the Kata repositories are updated with a new version, they need to be
+tagged.
+
 The `tag_repos.sh` script is used to create tags for the Kata Containers
-repositories. This script ensures that all the repositories are in the
-same version (by checking the `VERSION` file).
+repositories. This script ensures that all the repositories are in the same
+version (by checking the `VERSION` file).
 
-The script creates an **annotated tag** for the new release version for
-the following repositories:
+The script creates an **annotated tag** for the new release version for the
+following repositories:
 
 - agent
 - proxy
 - runtime
 - shim
 - throttler
 
-The script also tags the tests and osbuilder repositories to make it clear
-which versions of these supporting repositories are used for the release.
+The script also tags the tests and osbuilder repositories to make it clear which
+versions of these supporting repositories are used for the release.