Use a default machine of 'pc' rather than 'pc-1.0'

The 'pc-1.0' was available via qemu-system-x86_64 on CentOS 7, but this is no
longer available on CentOS 8.

Author: markgoddard

tasks/main.yml

@@ -29,7 +29,7 @@
     console_log_path: >-
       {{ vm.console_log_path |
          default(libvirt_vm_default_console_log_dir + '/' +  vm.name + '-console.log', true) }}
-    machine_default: "{{ none if libvirt_vm_engine == 'kvm' else 'pc-1.0' }}"
+    machine_default: "{{ none if libvirt_vm_engine == 'kvm' else 'pc' }}"
     machine: "{{ vm.machine | default(machine_default, true) }}"
     cpu_mode: "{{ vm.cpu_mode | default(libvirt_cpu_mode_default) }}"
     volumes: "{{ vm.volumes | default([], true) }}"