be compatible with gherkin library changes

the downside is that if outline examples are empty
it won't be pretty printed as node. But that does not make
much difference anyway

fmt.go

@@ -221,7 +221,9 @@ func (f *basefmt) Summary() {
 				total++
 			case *gherkin.ScenarioOutline:
 				for _, ex := range t.Examples {
-					total += len(ex.TableBody)
+					if examples, hasExamples := examples(ex); hasExamples {
+						total += len(examples.TableBody)
+					}
 				}
 			}
 		}

fmt_pretty.go

@@ -122,7 +122,13 @@ func (f *pretty) printOutlineExample(outline *gherkin.ScenarioOutline) {
 	var msg string
 	clr := green
 
-	example := outline.Examples[f.outlineNumExample]
+	ex := outline.Examples[f.outlineNumExample]
+	example, hasExamples := examples(ex)
+	if !hasExamples {
+		// do not print empty examples
+		return
+	}
+
 	firstExample := f.outlineNumExamples == len(example.TableBody)
 	printSteps := firstExample && f.outlineNumExample == 0
 

gherkin.go

@@ -0,0 +1,10 @@
+package godog
+
+import "gopkg.in/cucumber/gherkin-go.v3"
+
+// examples is a helper func to cast gherkin.Examples
+// or gherkin.BaseExamples if its empty
+func examples(ex interface{}) (*gherkin.Examples, bool) {
+	t, ok := ex.(*gherkin.Examples)
+	return t, ok
+}

suite.go

@@ -265,9 +265,16 @@ func (s *Suite) skipSteps(steps []*gherkin.Step) {
 func (s *Suite) runOutline(outline *gherkin.ScenarioOutline, b *gherkin.Background) (failErr error) {
 	s.fmt.Node(outline)
 
-	for _, example := range outline.Examples {
-		s.fmt.Node(example)
+	for _, ex := range outline.Examples {
+		example, hasExamples := examples(ex)
+		if !hasExamples {
+			// @TODO: may need to print empty example node, but
+			// for backward compatibility, cannot cast to *gherkin.ExamplesBase
+			// at the moment
+			continue
+		}
 
+		s.fmt.Node(example)
 		placeholders := example.TableHeader.Cells
 		groups := example.TableBody