Update swagger to 0.20.1 (#8010)

* update swagger to 0.20.1

* fiw swagger version for validate

vendor/github.com/stretchr/testify/require/require.go.tmpl

@@ -1,6 +1,6 @@
 {{.Comment}}
 func {{.DocInfo.Name}}(t TestingT, {{.Params}}) {
-	if assert.{{.DocInfo.Name}}(t, {{.ForwardedParams}}) { return }
 	if h, ok := t.(tHelper); ok { h.Helper() }
+	if assert.{{.DocInfo.Name}}(t, {{.ForwardedParams}}) { return }
 	t.FailNow()
 }