set mastodon version through env variable

linux/debian/K8S/fix-dns.yml

 - name: fix K8S DNS
   hosts: all
+  become: true
   tasks:
   - name: remove old DNS config
     ansible.builtin.file:
@@ -16,4 +17,3 @@
       dest: /var/lib/kubelet/kubeadm-flags.env
       content: |
         KUBELET_KUBEADM_ARGS="--container-runtime-endpoint=unix:///var/run/containerd/containerd.sock --pod-infra-container-image=registry.k8s.io/pause:3.9 --resolv-conf=/etc/resolv.conf"
-      
\ No newline at end of file

linux/debian/mastodon-update.yml

 - name: update mastodon server
   hosts: all
+  vars:
+    mastodon_version: {{ mastodon_version }}
   tasks:
     - name: 'update packages'
       apt:
@@ -21,14 +23,6 @@
       shell: |
         cd /home/mastodon/live
         git fetch --tags
-    - name: 'determine latest mastodon version'
-      become: yes
-      become_user: mastodon
-      become_method: su
-      shell: |
-        cd /home/mastodon/live
-        git describe --tags $(git rev-list --tags --max-count=1)
-      register: mastodon_version
     - name: 'update mastodon'
       become: yes
       become_user: mastodon