[gimp-web/oscp] Build from the testing branch, not migrate/testing

[Michael Schumacher <schumaml src gnome org>]

commit 1bd00cfe16e6bf64d8f75039bdb2576918001a65
Author: Michael Schumacher <schumaml gmx de>
Date:   Tue May 25 00:02:57 2021 +0200

    Build from the testing branch, not migrate/testing

 testing.gimp.org/Dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/testing.gimp.org/Dockerfile b/testing.gimp.org/Dockerfile
index 581352d5..38b08d7d 100644
--- a/testing.gimp.org/Dockerfile
+++ b/testing.gimp.org/Dockerfile
@@ -1,7 +1,7 @@
 FROM centos:8
 RUN dnf install -y python3-pip git make
 
-RUN git clone --depth 1 --branch migrate/testing https://gitlab.gnome.org/Infrastructure/gimp-web && \
+RUN git clone --depth 1 --branch testing https://gitlab.gnome.org/Infrastructure/gimp-web && \
     cd gimp-web && \
     python3 -m venv py3-venv && \
     source py3-venv/bin/activate && \