<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
The default `port` value of the `open_iscsi` module throws a type int to string conversion warning.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
- open_iscsi

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.9.3
  config file = /Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg
  configured module search path = [u'/Users/pascal/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/.venv/lib/python2.7/site-packages/ansible
  executable location = /Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/.venv/bin/ansible
  python version = 2.7.16 (default, Nov  9 2019, 05:55:08) [GCC 4.2.1 Compatible Apple LLVM 11.0.0 (clang-1100.0.32.4) (-macos10.15-objc-s
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
ANSIBLE_PIPELINING(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = True
ANSIBLE_SSH_ARGS(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = -o ControlMaster=auto -o ControlPersist=60s
ANSIBLE_SSH_CONTROL_PATH(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = %(directory)s/ansible-ssh-%%h-%%p-%%r
DEFAULT_BECOME(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = True
DEFAULT_FORKS(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = 20
DEFAULT_HOST_LIST(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = [u'/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/hosts']
DEFAULT_MANAGED_STR(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = !!! WARNING: This file is managed by Ansible, DON'T EDIT it manually !!!
DEFAULT_ROLES_PATH(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = [u'/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/roles']
INTERPRETER_PYTHON(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = /usr/bin/python3
RETRY_FILES_ENABLED(/Users/pascal/Documents/02_business/01_confirm/confirm-git/infrastructure/ansible.cfg) = False
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
```
╰─ lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 10 (buster)
Release:	10
Codename:	buster
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: perform a discovery and show available target nodes
  open_iscsi:
    show_nodes: yes
    discover: yes
    portal: '{{ iscsi_server }}'
  tags:
    - iscsi
    - config
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->

```paste below
TASK [iscsi : perform a discovery and show available target nodes] *********************************************************************************************************************************************************************************************************************************************************
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
TASK [iscsi : perform a discovery and show available target nodes] *********************************************************************************************************************************************************************************************************************************************************
[WARNING]: The value 3260 (type int) in a string field was converted to '3260' (type string). If this does not look like what you expect, quote the entire value to ensure it does not change.
```

version_added: "1.4"
short_description: Manage iSCSI targets with Open-iSCSI
description:
    - Discover targets on given portal, (dis)connect targets, mark targets to
      manually or auto start, return device nodes of connected targets.
requirements:
    - open_iscsi library and tools (iscsiadm)
options:
    portal:
        description:
        - The IP address of the iSCSI target.
        type: str
        aliases: [ ip ]
    port:
        description:
        - The port on which the iSCSI target process listens.
        type: str
        default: 3260
    target:
        description:
        - The iSCSI target name.
        type: str
        aliases: [ name, targetname ]
    login:
        description:
        - Whether the target node should be connected.
        type: bool
        aliases: [ state ]
    node_auth:
        description: