Update tests to use gotest.tools angel

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

cio/io_test.go

@@ -32,8 +32,8 @@ import (
 
 	"github.com/containerd/fifo"
 	"github.com/google/go-cmp/cmp/cmpopts"
-	"github.com/gotestyourself/gotestyourself/assert"
-	is "github.com/gotestyourself/gotestyourself/assert/cmp"
+	"gotest.tools/assert"
+	is "gotest.tools/assert/cmp"
 )
 
 func assertHasPrefix(t *testing.T, s, prefix string) {

cio/io_unix_test.go

@@ -23,7 +23,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"github.com/gotestyourself/gotestyourself/assert"
+	"gotest.tools/assert"
 )
 
 func TestOpenFifos(t *testing.T) {