Update etcd to 3.6 (#12634)

* [etcd] Update etcd 3.5.x to 3.6.5

- Add hashes for etcd 3.6.5
- Remove etcd v2 backup task for etcd 3.6
  The etcd 3.6 removes 'etcdctl backup' command with ETCDCTL_API=2
- Downgrade etcd to 3.5 in netchecker
  The netchecker does not work with etcd 3.6 becaust it removes v2 API support (--enable-v2).
  And netchekcer does not support v3 API.

* Fix: Change etcd config to clean up v2 store before upgrading etcd to 3.6

* Bump etcd to 3.6.8

roles/etcd/tasks/main.yml

@@ -53,6 +53,12 @@
     - control-plane
     - network
 
+- name: Install etcd
+  include_tasks: "install_{{ etcd_deployment_type }}.yml"
+  when: ('etcd' in group_names)
+  tags:
+    - upgrade
+
 - name: Install etcdctl and etcdutl binary
   import_role:
     name: etcdctl_etcdutl
@@ -64,12 +70,6 @@
     - ('etcd' in group_names)
     - etcd_cluster_setup
 
-- name: Install etcd
-  include_tasks: "install_{{ etcd_deployment_type }}.yml"
-  when: ('etcd' in group_names)
-  tags:
-    - upgrade
-
 - name: Configure etcd
   include_tasks: configure.yml
   when: ('etcd' in group_names)