Add heddn as a comaintainer to get a D11-compatible release out

@heddn thanks!!

FYI, we've been using layout_builder_st successfully with Drupal 11.1.x (layout_builder_st 2.0.x) for months now.

Curiously the stats say that there's 0 installs for 2.0.x however that is untrue, I know of several and they're not getting reported.

I assume this situation will rectify it'self once 2.0.0-rc1/beta1/alpha1 is tagged

BTW, we're using 2.0.x with these patches:

                    "drupal/layout_builder_st": {
                        "3411037 - Fix core removing contextual translation links": "https://git.drupalcode.org/project/layout_builder_st/-/merge_requests/5.patch",
                        "3420063 - Call to a member function getConfig() OverridesSectionStorage.php": "https://git.drupalcode.org/project/layout_builder_st/-/merge_requests/6.diff",
                         "3069964 - Null fix for moderation dashboard, otherwise WSOD on login": "https://www.drupal.org/files/issues/2025-01-02/3069964-null-fix.patch"
                    },

Automatically closed - issue fixed for 2 weeks with no activity.