move runc version to a separate file for easier consumption

This moves the runc version to build to scripts/setup/runc-version,
which makes it easier for packagers to find the default version
to use.

The RUNC_VERSION environment variable can still be used to override
the version, which can be used (e.g.) to test against different versions
in our CI.

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

contrib/Dockerfile.test

@@ -36,7 +36,7 @@ RUN apt-get update && apt-get install -y \
     libseccomp-dev \
   --no-install-recommends
 
-COPY script/setup/install-runc install-runc
+COPY script/setup/runc-version script/setup/install-runc ./
 # Allow overriding the version of runc to install through build-args
 ARG RUNC_VERSION
 ARG GOPROXY=direct