[gnome-software] trivial: Fix tiny compile warning nit

[Richard Hughes <rhughes src gnome org>]

commit cc2b2766c6fd08462023fd92509d563d8bf0cc46
Author: Richard Hughes <richard hughsie com>
Date:   Tue Jun 30 12:38:46 2020 +0100

    trivial: Fix tiny compile warning nit

 src/gs-details-page.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/gs-details-page.c b/src/gs-details-page.c
index 8c7e36e1..9207eaee 100644
--- a/src/gs-details-page.c
+++ b/src/gs-details-page.c
@@ -1713,7 +1713,8 @@ gs_details_page_content_rating_set_css (GsDetailsPage *page, guint age)
        g_string_append_printf (css, "color: %s;\n", color_fg);
        g_string_append_printf (css, "background-color: %s;\n", color_bg);
 
-       gs_utils_widget_set_css (page->button_details_rating_value, 
&page->button_details_rating_style_provider,
+       gs_utils_widget_set_css (page->button_details_rating_value,
+                                (GtkCssProvider **) &page->button_details_rating_style_provider,
                                 "content-rating-custom", css->str);
 }