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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


- with C(state=present) force option allow to overwrite existing container
      - with states C(stopped) , C(restarted) allow to force stop instance
    type: bool
    default: 'no'
  state:
    description:
     - Indicate desired state of the instance
    choices: ['present', 'started', 'absent', 'stopped', 'restarted']
    default: present
  pubkey:
    description:
      - Public key to add to /root/.ssh/authorized_keys. This was added on Proxmox 4.2, it is ignored for earlier versions
    version_added: "2.3"
  unprivileged:
    version_added: "2.3"
    description:
      - Indicate if the container should be unprivileged
    type: bool
    default: 'no'
notes:
  - Requires proxmoxer and requests modules on host. This modules can be installed with pip.
requirements: [ "proxmoxer", "python >= 2.7", "requests" ]
author: Sergei Antipov (@UnderGreen)
'''
EXAMPLES = '''
# Create new container with minimal options
- proxmox:
    vmid: 100
    node: uk-mc02
    api_user: root@pam