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>

plugin/plugin.go

@@ -44,7 +44,7 @@ var (
 
 // IsSkipPlugin returns true if the error is skipping the plugin
 func IsSkipPlugin(err error) bool {
-	return errors.Cause(err) == ErrSkipPlugin
+	return errors.Is(err, ErrSkipPlugin)
 }
 
 // Type is the type of the plugin