Update to 0.49.2

Changelog:
Hugo 0.49 brings directory based archetypes and also improves the language handling in
hugo new. This should simplify working with page bundles. One example of this would be
how you now can create a new showcase for the Hugo web site.

But this release is also about collections. Go 1.11 gave us variable overwrite support in
Go templates. That made it possible to simplify a lot of template constructs, but it also
showed some limitations in Hugo's template functions. So with this release we have:

• added append function to append to collections.
• added group to create custom page groups.
• improved the type support in slice.

PR: 232343
Submitted by: ben.lavery@hashbang0.com <ben.lavery@hashbang0.com> (maintainer)
Sponsored by: Netzkommune GmbH