* feat(vendir): support extracting HTTP sources
As noted in #41435, Vendir's support for HTTP sources would be useful
for Renovate to keep updated.
Instead of managing the updating of files ourselves, we can use Vendir's
existing `lockFileMaintenance` task to do so, where `vendir sync` will
re-fetch the remote file(s) and sync them to the repo.
For this to be supported, we can extract the HTTP sources with
`unsupported-datasource`, so Renovate knows that the dependency is
there, but can't be managed by us.
This makes it possible to extract HTTP dependencies, and then have
Renovate update them through `lockFileMaintenance`.
* fixup! feat(vendir): support extracting HTTP sources
Jamie Tanna