Update to bluemonday-1.0.6 (#15294)

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/markup/sanitizer_test.go

@@ -6,6 +6,8 @@
 package markup
 
 import (
+	"html/template"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -50,3 +52,13 @@ func Test_Sanitizer(t *testing.T) {
 		assert.Equal(t, testCases[i+1], string(SanitizeBytes([]byte(testCases[i]))))
 	}
 }
+
+func TestSanitizeNonEscape(t *testing.T) {
+	descStr := "<scrİpt>&lt;script&gt;alert(document.domain)&lt;/script&gt;</scrİpt>"
+
+	output := template.HTML(Sanitize(string(descStr)))
+	if strings.Contains(string(output), "<script>") {
+		t.Errorf("un-escaped <script> in output: %q", output)
+	}
+
+}