The [GitHub documentation][1] for FUNDING.yml specifically notes that if a
custom URL is in the Array format, and includes `:` then it must be
quoted.
From this we can infer that the custom URL does not have to contain a
`:` at all.
The example for a Custom URL also gives an example of an unquoted URL
without any `:` character:
```
custom: ["https://www.paypal.me/octocat", octocat.com]
```
However if a repository uses a URL in this format it is currently
rejected because it does not specify a scheme. Furthermore the
`parse_url` method treats the `octocat.com` example as a path and not a
host. The same is true for URLs such as
`octocat.com/funding/example.html`.
This patch adds an additional allowance for the URL filter to capture
the case where a URL has no scheme or host, but does have a path.
[1]: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/displaying-a-sponsor-button-in-your-repository#about-funding-files
811dfd3a13