Align Group blocks left or right

OK, I found a way to do this after browsing the source code. I do note that the code that helped me lives under deprecated.js so it’s possible this won’t continue to work.

Here’s the JS code I have in my plugin directory

function addAlignmentToGroups(settings, name) {
    if (name !== "core/group") {
        return settings;
    }

    return lodash.assign({}, settings, {
        supports: lodash.assign( {}, settings.supports, {
            align: ['wide', 'full', 'left', 'center', 'right']
        })
    });
}

wp.hooks.addFilter(
    'blocks.registerBlockType',
    'myapp/alignments/group-block',
    addAlignmentToGroups
);

And the PHP code to load it:

<?php

 function my_enqueue() {
     wp_enqueue_script(
         'my-align-blocks',
         plugins_url('dist/align-blocks.js', __FILE__),
         ['wp-blocks']
     );
 }

 add_action('enqueue_block_editor_assets', 'my_enqueue');