add krew_download_url to offline.yml (#9788)

inventory/sample/group_vars/all/offline.yml

@@ -72,6 +72,9 @@
 # gvisor_runsc_download_url: "{{ files_repo }}/storage.googleapis.com/gvisor/releases/release/{{ gvisor_version }}/{{ ansible_architecture }}/runsc"
 # gvisor_containerd_shim_runsc_download_url: "{{ files_repo }}/storage.googleapis.com/gvisor/releases/release/{{ gvisor_version }}/{{ ansible_architecture }}/containerd-shim-runsc-v1"
 
+# [Optional] Krew: only if you set krew_enabled: true
+# krew_download_url: "{{ files_repo }}/github.com/kubernetes-sigs/krew/releases/download/{{ krew_version }}/krew-{{ host_os }}_{{ image_arch }}.tar.gz"
+
 ## CentOS/Redhat/AlmaLinux
 ### For EL7, base and extras repo must be available, for EL8, baseos and appstream
 ### By default we enable those repo automatically