Replace errors.Cause() with errors.Is()

Dependencies may be switching to use the new `%w` formatting
option to wrap errors; switching to use `errors.Is()` makes
sure that we are still able to unwrap the error and detect the
underlying cause.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

remotes/docker/resolver.go

@@ -283,7 +283,7 @@ func (r *dockerResolver) Resolve(ctx context.Context, ref string) (string, ocisp
 			log.G(ctx).Debug("resolving")
 			resp, err := req.doWithRetries(ctx, nil)
 			if err != nil {
-				if errors.Cause(err) == ErrInvalidAuthorization {
+				if errors.Is(err, ErrInvalidAuthorization) {
 					err = errors.Wrapf(err, "pull access denied, repository does not exist or may require authorization")
 				}
 				// Store the error for referencing later