Unify branch names for odh-manifests and notebooks

Notebooks branch can be set explicitly via --notebooks-branch

Signed-off-by: Andrej Podhradsky <apodhrad@redhat.com>

README.md

@@ -44,4 +44,9 @@ To get help about the script
 ./rhods-disconnected-helper.sh -h
 ```
 
-After running the script, the list of images with an example will be saved in a file by default called rhods-< version >.md with version the version of RHODS you are using.
+After running the script, the list of images with an example will be saved in a file by default called rhods-< version >.md with version the version of RHODS you are using.
+
+By default, the repositories for odh-manifests and notebooks are checked out to the same branch (rhods version). To use different notebooks branch, execute
+```bash
+./rhods-disconnected-helper.sh --rhods-version <version> --notebooks-branch <branch>
+```

rhods-disconnected-helper.sh

@@ -8,7 +8,7 @@ set_defaults() {
   rhods_version="${rhods_version:-}"
   repository_folder="${repository_folder:-.odh-manifests}"
   notebooks_folder="${notebooks_folder:-.odh-notebooks}"
-  notebooks_branch="${notebooks_branch:-release-2023a}"
+  notebooks_branch="${notebooks_branch:-}"
   file_name="${file_name:-$rhods_version.md}"
   skip_tls="${skip_tls:-false}"
   mirror_url="${mirror_url:-registry.example.com:5000/mirror/oc-mirror-metadata}"
@@ -32,6 +32,7 @@ function help() {
   echo "  --set-registry  Set the registry"
   echo "  --set-openshift-version  Set the OpenShift version"
   echo "  --set-channel  Set the channel"
+  echo "  --notebooks-branch  Set the notebooks branch"
 }
 
 function get_latest_rhods_version() {
@@ -186,6 +187,13 @@ function change_rhods_version() {
     echo "Error: Version $rhods_version does not exist"
     exit 1
   fi
+
+  # Set the same version for notebooks if not set otherwise via
+  #   --notebooks-branch <notebooks_branch>
+  if [ -z "${notebooks_branch}" ]; then
+    notebooks_branch="${rhods_version}"
+  fi
+
   echo "Switching to $rhods_version"
   git switch "$rhods_version"
   return 0
@@ -244,6 +252,11 @@ parse_args() {
       shift
       shift
       ;;
+    --notebooks-branch)
+      notebooks_branch="$2"
+      shift
+      shift
+      ;;
     --skip-image-verification)
       skip_image_verification=true
       shift