[gegl] tests: xml tests output is in TAP format

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 6db44bb0d32a428d1366c58da1ad5074a53de81a
Author: John <jtm home gmail com>
Date:   Sat Jul 18 10:46:34 2020 +0100

    tests: xml tests output is in TAP format

 tests/xml/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/tests/xml/meson.build b/tests/xml/meson.build
index 61388df27..00c3f8824 100644
--- a/tests/xml/meson.build
+++ b/tests/xml/meson.build
@@ -14,6 +14,7 @@ foreach _test : xml_tests
       link_with: gegl_lib,
     ),
     env: gegl_test_env,
+    protocol: 'tap',
     suite: 'xml',
     is_parallel: gegl_test_parallel,
   )