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##### SUMMARY
An hour ago I upgraded my Proxmox to the new stable version 6. Since then my playbooks fail with this error:
`fatal: [proxmox]: FAILED! => {"changed": false, "msg": "authorization on proxmox cluster failed with exception: could not convert string to float: '6.0-4'"}`

It seems like the proxmox changed the API.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
proxmox (https://github.com/mrdrogdrog/ansible/blob/6430205d396b7c1733de22a898c51823f67d5bf4/lib/ansible/modules/cloud/misc/proxmox.py#L484)

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```
ansible 2.8.2
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/tilman/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 3.7.3 (default, Jun 24 2019, 04:54:02) [GCC 9.1.0]
```


##### OS / ENVIRONMENT
Proxmox 6 


##### STEPS TO REPRODUCE
- Use the latest ansible version
- Use the latest stable version of proxmox (6)
- Use the proxmox module to do anything. E.g. create a container
- Get the error


##### EXPECTED RESULTS
Normal runthrough

##### ACTUAL RESULTS
Crash with an error


module.fail_json(msg='Unable to revert settings on VM {0} with vmid {1}: Maybe is not a pending task...   '.format(name, vmid) + str(e))
    if state == 'present':
        try:
            if get_vm(proxmox, vmid) and not (update or clone):
                module.exit_json(changed=False, msg="VM with vmid <%s> already exists" % vmid)
            elif get_vmid(proxmox, name) and not (update or clone):
                module.exit_json(changed=False, msg="VM with name <%s> already exists" % name)
            elif not (node, name):
                module.fail_json(msg='node, name is mandatory for creating/updating vm')
            elif not node_check(proxmox, node):
                module.fail_json(msg="node '%s' does not exist in cluster" % node)
            create_vm(module, proxmox, vmid, newid, node, name, memory, cpu, cores, sockets, timeout, update,
                      acpi=module.params['acpi'],
                      agent=module.params['agent'],
                      autostart=module.params['autostart'],
                      balloon=module.params['balloon'],
                      bios=module.params['bios'],
                      boot=module.params['boot'],
                      bootdisk=module.params['bootdisk'],
                      cpulimit=module.params['cpulimit'],
                      cpuunits=module.params['cpuunits'],
                      description=module.params['description'],
                      digest=module.params['digest'],
                      force=module.params['force'],
                      freeze=module.params['freeze'],
                      hostpci=module.params['hostpci'],
                      hotplug=module.params['hotplug'],
                      hugepages=module.params['hugepages'],
                      ide=module.params['ide'],
                      keyboard=module.params['keyboard'],