versions: Add xurls utility

[jodh-intel]

Add the xurls utility to the
versions database. This tool is used by the CI scripts in the tests
repo to check URLs for validity. However, the latest version of xurls
requires golang 1.10.3+, but we don't need to use the latest version and
doing so is causing us problems (see
kata-containers/kata-containers#32).

Fixes #854.

Signed-off-by: James O. D. Hunt james.o.hunt@intel.com

[grahamwhaley]

I think pinning this, particularly for older stable branches (so they don't rot as the tools move forwards), is the right thing to do...
lgtm

[jodh-intel]

This fix will allow the tests CI to be updated to install the correct version of xurls for a particular stable branch. However, this YAML could arguably could be added the tests versions database instead:

• https://github.com/kata-containers/tests/blob/master/versions.yaml

Either way, we need to use a pinned version of xurls in the stable branches to fix the CI failures on these PRs:

• create/run: Make bundle path default to cwd #836
• create/run: Make bundle path default to cwd #838

... or we have to backport the golang 1.10.4 fix to all stable branches:

• versions: Update golang to 1.10.4 #744

@egernst, @gnawux, @grahamwhaley, @chavafg - any thoughts on what the best approach is here?

[grahamwhaley]

The principle of backports to stable branches for new versions of golang (be that in our code or code and tools we import), feels wrong. They are stable, so we should not be injecting a bunch of flux.
Pinning items feels like a more sustainable fix to me (at some upfront cost of doing some config setup)

[chavafg]

@jodh-intel I would prefer that this xurls version should go in the versions.yaml of the tests repository as it is a tool only used for testing purposes.

[jodh-intel]

@chavafg - wfm. I'll close this PR and probably handle it on kata-containers/tests#856...