Allow blank tags with severity

v2/pkg/templates/compile.go

@@ -48,7 +48,7 @@ func Parse(filePath string, options protocols.ExecuterOptions) (*Template, error
 	if len(options.Options.Tags) > 0 {
 		templateTags, ok := template.Info["tags"]
 		if !ok {
-			return nil, nil
+			templateTags = ""
 		}
 		if err := matchTemplateWithTags(types.ToString(templateTags), types.ToString(template.Info["severity"]), options.Options); err != nil {
 			return nil, nil

v2/pkg/templates/compile_test.go

@@ -34,4 +34,9 @@ func TestMatchTemplateWithTags(t *testing.T) {
 		err = matchTemplateWithTags("lang:php,os:linux,cms:symfony", "low", &types.Options{Tags: []string{"low"}})
 		require.Nil(t, err, "could get key value tag for severity")
 	})
+
+	t.Run("blank-tags", func(t *testing.T) {
+		err = matchTemplateWithTags("", "low", &types.Options{Tags: []string{"jira"}})
+		require.NotNil(t, err, "could get value tag for blank severity")
+	})
 }