Disable updates-testing repo in the fedora-latest Docker image

This is to prevent buggy packages in testing repo breaking CI. If the
user wishes to add the repo explicitly, he can edit the builddep step
in the runner configuration, or request for the addition of the
dependencies to freeipa copr repositories.

data/dockerfiles/fedora/latest/Dockerfile

@@ -2,7 +2,7 @@ FROM martbab/freeipa-fedora-builder:master-latest
 ENV container=docker LANG=en_US.utf8 LANGUAGE=en_US.utf8 LC_ALL=en_US.utf8
 
 RUN dnf copr enable -y @freeipa/freeipa-4-4 \
-    && dnf config-manager --set-enabled updates-testing \
+    && dnf config-manager --set-disabled updates-testing \
     && dnf install -y freeipa-server freeipa-server-dns \
         freeipa-server-trust-ad python-ipatests --best --allowerasing \
     && dnf clean all \