Ensure the generated ssh key id_rsa is rsa

the runner's default is now ed25519

Author: elelaysh

.github/workflows/multinode.yml

@@ -206,7 +206,7 @@ jobs:
           echo vxlan_vni=$vni >> $GITHUB_OUTPUT
 
       - name: Generate SSH keypair
-        run: ssh-keygen -f id_rsa -N ''
+        run: ssh-keygen -t rsa -f id_rsa -N ''
         working-directory: ${{ github.workspace }}/terraform-kayobe-multinode
 
       # NOTE: In Ansible 2.10 and lower the synchronize module used in the