update validation for Simplified Software Upgrade

[mksbcisco]

validate direct upgrades from 10.1.x or 10.2.x to 11.1.x version.

Description

As part of Simplified Software Upgrade feature (https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-new-features/management-features/simplified-software-upgrade) where we can upgrade PAN-OS from ver 10.1.x/10.2.x directly to 11.1.x (provided we have base software 11.1.0 downloaded), same feature from Ansible can now be used

Motivation and Context

This problem solves indirect multi-path upgrade
i.e 10.1.8 -> 11.0.0 -> 11.1.0 -> 11.1.x version to be upgraded in a single path upgrade to 10.1.8 -> 11.1.x

Also, a reported bug #553

How Has This Been Tested?

I have tested the function using my use-case of current version as 10.1.12 and target version of 11.1.6
The actual PANOS has been tested for upgrade and the same was successful without any issue

def is_valid_sequence(current, target):
    current_major = int(current.split('.')[0])
    target_major = int(target.split('.')[0])
    current_minor = int(current.split('.')[1])
    target_minor = int(target.split('.')[1])
    # Patch version change (major and minor versions match)
    if (current_major == target_major) and (current_minor == target_minor):
        print(1)
        return True

    # Upgrade minor version (9.0.0 -> 9.1.0)
    elif (current_major == target_major) and (current_minor + 1 == target_minor):
        print(2)
        return True

    # Upgrade major version (9.1.0 -> 10.0.0)
    elif (current_major + 1 == target_major) and (target_minor == 0):
        print(3)
        return True

    elif ((current_major == 10) and (current_minor == 1 or current_minor == 2)) and (target_major == 11 and target_minor == 1):
          print(3.5)
          return True

    # Downgrade minor version (9.1.0 -> 9.0.0)
    elif (current_major == target_major) and (current_minor - 1 == target_minor):
        print(4)
        return True

    # Downgrade major version (10.0.3 -> 9.1.6)
    elif current_major - 1 == target_major:
        print(5)
        return True

    else:
        return False

print(is_valid_sequence('10.1.12', '11.1.6'))

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes if appropriate.
• All new and existing tests passed.