Ensure update count values are a number

[kfiresmith]

In rare cases, this script captures bad data due to APT repos being broken.

We should ensure we are capturing a valid number when we write out all_updates and security_updates values.

Example:

        "all_updates": "E: Error: BrokenCount > 0",
        "date_collected": "2021-06-29T11:59+0000",
        "eol": "true",
        "errata_support": "true",
        "needs_reboot": "false",
        "os_updates_broken": "true",
        "security_updates": "E: Error: BrokenCount > 0"