[gtk/creiter-glib-sub-test] try with the 64bit toolchain

[Christoph Reiter <creiter src gnome org>]

commit ce9a22b18ac9c5f65f50388b2169095f36b0632c
Author: Christoph Reiter <creiter src gnome org>
Date:   Sat Jan 26 17:01:19 2019 +0100

    try with the 64bit toolchain

 .gitlab-ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b60004ae1e..2860ead649 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -37,9 +37,9 @@ fedora-x86_64:
     key: "%CI_JOB_NAME%"
     <<: *cache-paths
 
-msys2-mingw32:
+msys2-mingw64:
   variables:
-    MSYSTEM: "MINGW32"
+    MSYSTEM: "MINGW64"
     CHERE_INVOKING: "yes"
   <<: *mingw-defaults