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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


net         : '{"net0":"virtio,bridge=vmbr1,rate=200", "net1":"e1000,bridge=vmbr2,"}'
# Create new VM with one network interface, three virto hard disk, 4 cores, and 2 vcpus.
- proxmox_kvm:
    api_user    : root@pam
    api_password: secret
    api_host    : helldorado
    name        : spynal
    node        : sabrewulf
    net         : '{"net0":"virtio,bridge=vmbr1,rate=200"}'
    virtio      : '{"virtio0":"VMs_LVM:10", "virtio1":"VMs:2,format=qcow2", "virtio2":"VMs:5,format=raw"}'
    cores       : 4
    vcpus       : 2
# Clone VM with only source VM name
- proxmox_kvm:
    api_user    : root@pam
    api_password: secret
    api_host    : helldorado
    clone       : spynal   # The VM source
    name        : zavala  # The target VM name
    node        : sabrewulf
    storage     : VMs
    format      : qcow2
    timeout     : 500  # Note: The task can take a while. Adapt
# Clone VM with source vmid and target newid and raw format
- proxmox_kvm:
    api_user    : root@pam
    api_password: secret
    api_host    : helldorado
    clone       : arbitrary_name
    vmid        : 108