Perhaps we should allow this to be overridden with an attribute specifying a regex.

For example, some people, instead of using `1.0.2-SNAPSHOT` will use `1.0.2.sha.5114f85` to specify which commit hash the snapshot is built from. In that case, the cookbook writer would override an attribute (for example `node['artifact']['snapshot_regex']`) to be `"\.sha\.[a-z0-9]+$"`.

This code could look like this instead:

artifact-cookbook/attributes/default.rb
```ruby
default['artifact']['snapshot_regex'] = "-SNAPSHOT$"
```
artifact-cookbook/libraries/chef_artifact.rb
```ruby
def snapshot?(version)
  !!version.match(/#{node['artifact']['snapshot_regex']}/)
end
```

This would also address the case where the snapshot segment of a version is not at the end of the version. The custom regex could match any part of the string.

The above example defaults to matching `-SNAPSHOT` at the end of the string, just the same as you have implemented here.