Dockerfile: temporarily skip CRIU stage

The package repository currently has issues;

    => ERROR https://download.opensuse.org/repositories/devel:/tools:/criu/Debian_11/Release.key

The only test currently using this binary is currently skipped, as the test
was broken;
https://github.com/moby/moby/blob/6e98a7f2c9184d4e91df8abf06e2245a0cd77c58/integration/container/checkpoint_test.go#L32-L33

So let's disable this stage for the time being.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Dockerfile

@@ -447,7 +447,12 @@ COPY --from=tomll         /build/ /usr/local/bin/
 COPY --from=gowinres      /build/ /usr/local/bin/
 COPY --from=tini          /build/ /usr/local/bin/
 COPY --from=registry      /build/ /usr/local/bin/
-COPY --from=criu          /build/ /usr/local/bin/
+
+# Skip the CRIU stage for now, as the opensuse package repository is sometimes
+# unstable, and we're currently not using it in CI.
+#
+# FIXME(thaJeztah): re-enable this stage when https://github.com/moby/moby/issues/38963 is resolved (see https://github.com/moby/moby/pull/38984)
+# COPY --from=criu          /build/ /usr/local/bin/
 COPY --from=gotestsum     /build/ /usr/local/bin/
 COPY --from=golangci_lint /build/ /usr/local/bin/
 COPY --from=shfmt         /build/ /usr/local/bin/