@return [String] the name of the source of explicit dependencies, i.e.
those passed to {Resolver#resolve} directly.
@return [String] the name of the source of ‘locked’ dependencies, i.e.
those passed to {Resolver#resolve} directly as the `base`
Creates a new URI
formatter for uri
.
Normalize the URI
by adding “http://” if it is missing.
Parses the uri, raising if it’s invalid
Parses the uri, returning the original uri if it’s invalid