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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


update:
    description:
      - If C(yes), the VM will be update with new value.
      - Cause of the operations of the API and security reasons, I have disabled the update of the following parameters
      - C(net, virtio, ide, sata, scsi). Per example updating C(net) update the MAC address and C(virtio) create always new disk...
    type: bool
    default: 'no'
  validate_certs:
    description:
      - If C(no), SSL certificates will not be validated. This should only be used on personally controlled sites using self-signed certificates.
    type: bool
    default: 'no'
  vcpus:
    description:
      - Sets number of hotplugged vcpus.
  vga:
    description:
      - Select VGA type. If you want to use high resolution modes (>= 1280x1024x16) then you should use option 'std' or 'vmware'.
    choices: ['std', 'cirrus', 'vmware', 'qxl', 'serial0', 'serial1', 'serial2', 'serial3', 'qxl2', 'qxl3', 'qxl4']
    default: std
  virtio:
    description:
      - A hash/dictionary of volume used as VIRTIO hard disk. C(virtio='{"key":"value", "key":"value"}').
      - Keys allowed are - C(virto[n]) where 0 ≤ n ≤ 15.
      - Values allowed are -  C("storage:size,format=value").
      - C(storage) is the storage identifier where to create the disk.
      - C(size) is the size of the disk in GB.
      - C(format) is the drive's backing file's data format. C(qcow2|raw|subvol).
  vmid:
    description: