ci: install diffutils on openSUSE container

The test 81 needs the `diff` command and a recent openSUSE container
does not include it any more.

So explicitly install `diffutils`.

diff --git a/test/container/Dockerfile-opensuse b/test/container/Dockerfile-opensuse
index 446afcec39294684893a137099790b38e77c2313..5147a91113d3554e627b46d3de39c01a933dbf6f 100644 (file)
--- a/test/container/Dockerfile-opensuse
+++ b/test/container/Dockerfile-opensuse
@@ -20,6 +20,7 @@ RUN zypper --non-interactive install --no-recommends \
     cryptsetup \
     dhcp-client \
     dhcp-server \
+    diffutils \
     dnsmasq \
     distribution-gpg-keys \
     e2fsprogs \