constraint Parser Error

[vdice]

I've encountered the following issue by way of specifying a 'pre-release' Helm chart version dependency.

When specifying a chart version of, say, v2.3.5-sha.20d586f, it is happily parsed/constrained by this package and Helm is happy as well.

However, when adding a timestamp, resulting in a chart version of v2.3.5-20161202202307-sha.e8fc5e5, this package returns a constraint Parser Error from the following logic.

In local testing, semver.NewConstraint() seems to allow up to 10 digits for the timestamp without throwing this particular error -- is there a semver rule that is being broken here in using >10 digits (14 to be precise)? Or, might this be an addressable parsing issue in this package?

[mattfarina]

There is no rule about digit length. In this case the pre-release would be 20161202202307-sha.e8fc5e5. I'll take a look at it on Monday.

[mattfarina]

A PR was started in #35

[mattfarina]

@vdice Can you take a look at #36? I think this will fix it.