This cleans up the platforms package from dependencies that are not strictly
needed. This is in preparation of making this package a separate module, which
can be shared by plugins, and containerd versions (as well as external consumers),
- Remove dependency on the errdefs package: most uses of these error
definitions were used internally, and other errors may not be useful
for external consumers as sentinel errors.
- ErrInvalidArgument may be a potential exception, although a look at
current uses of this package shows that there's no special handling of
invalid parameters vs other errors (all would boil down to "the passed
platform is invalid" (either the format, or parsing is not implemented
on a specific platform)
- Remove uses of the convenience "Platform" alias in favor of using the
upstream (from OCI spec). Consumers of this package can still use the
convenience alias, but make sure that function signatures do not imply
that it's a different type (which can cause confusion).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
