containers: Specify COPR chroot explicitly (#1627)

A recent change to DNF COPR plugin [1] makes 'epel-9' the default chroot
used for CentOS Stream 9. Let's specify the 'centos-stream-9' chroot
name that we use in oVirt's COPR explictly.

[1] rpm-software-management/dnf-plugins-core#459

Signed-off-by: Marcin Sobczyk <msobczyk@redhat.com>

Signed-off-by: Marcin Sobczyk <msobczyk@redhat.com>

DEVELOPERS.md

@@ -30,7 +30,7 @@ for your platform to use the same packages that will be used by CI to build the
 
 For CentOS stream 9:
 
-    dnf copr enable -y ovirt/ovirt-master-snapshot
+    dnf copr enable -y ovirt/ovirt-master-snapshot centos-stream-9
     dnf install -y ovirt-engine-nodejs-modules
 
 **Note**: The project will not currently build on CentOS stream 9.  See