refactor: move ANSIBLE_HOST_KEY_CHECKING environment variable to update-proxmox job

.gitea/workflows/playbooks.yml

@@ -48,8 +48,6 @@ jobs:
       image: alpine/ansible:2.18.6
     steps:
       - name: Setup environment
-        env:
-          ANSIBLE_HOST_KEY_CHECKING: 'False'
         run: |
           apk add git
           git clone https://gitea.akshun-lab.uk/akshun/ansible.git /mnt
@@ -57,5 +55,7 @@ jobs:
           echo "${{ secrets.ANSIBLE_BECOME_PASS }}" > /mnt/become-pass.txt && \
           chmod 600 /mnt/default-key
       - name: Update proxmox nodes
+        env:
+          ANSIBLE_HOST_KEY_CHECKING: 'False'
         run: |
           ansible-playbook -i /mnt/inventory.yml --vault-pass-file /mnt/become-pass.txt --key-file /mnt/default-key /mnt/playbooks/update-proxmox.yml