PUV - accept tversion as input param

[monrog2]

Version to be passed as argument to cxscript
CC0 - 6.1(2f)
QA - 6.2(0.41)

CCO is priority, QA would need some lib update for handling version parsing + gt/lt logic.

include pytest for args

[monrog2]

multiple input parms requested at this point. Today's list:

def parse_args(args):
    parser = ArgumentParser(description="ACI Pre-Upgrade Validation Script - %s" % SCRIPT_VERSION)
    parser.add_argument("-t", "--tversion", action="store", type=str, help="Upgrade Target Version. Ex. 6.2(1a)")
    parser.add_argument("-c", "--cversion", action="store", type=str, help="Override Current Version. Ex. 6.1(1a)")
    parser.add_argument("-d", "--debug-function", action="store", type=str, help="Name of a single function to debug. Ex. 'apic_version_md5_check'")
    parser.add_argument("-a", "--api-only", action="store_true", help="For built-in PUV. API Checks only. Checks using SSH are skipped.")
    parser.add_argument("-n", "--no-cleanup", action="store_true", help="Skip all file cleanup after script execution.")
    parser.add_argument("-v", "--version", action="store_true", help="Show the script version.")
    parser.add_argument("--total-checks", action="store_true", help="Show the total number of checks.")
    parsed_args = parser.parse_args(args)
    return parsed_args