[Feature] Add fallback to get version if Github API fails

[abgox]

Feature Request

"checkver": "github",
"autoupdate": {
    "hash": {
        "mode": "github"
    }
}

• If we define it this way, it will consume two Github API requests.
  • I don't know whether the request data was cached or not.
  • But the focus here is not on how many API requests are consumed
• If there are more than 2,500 applications, it will exceed the API limit (5,000 requests/hour).
• Currently, if failed to get hash by API, it will fallback by downloading the installation package.
• But, if failed to get version by API, it will directly to the next app to check.

Describe the solution you'd like

If failed to get version by API:

1. First attempt to fetch version information by parsing the project release page. (It actually exists, but it is not used as a fallback.)
2. If web scraping also fails, then proceed to the next application's update check.

Related script file: https://github.com/ScoopInstaller/Scoop/blob/develop/bin/checkver.ps1