Migrate site build to new yaml-based operation

TL;DR: if your project web site is kept in subversion, disregard this email please. If your project web site is using git, and you have not deployed it via .asf.yaml, you MUST switch before July 1st or risk your web site goes stale.

Dear Apache projects,
In order to simplify our web site publishing services and improve self-serve for projects and stability of deployments, we will be turning off the old 'gitwcsub' method of publishing git web sites. As of this moment, this involves 120 web sites. All web sites should switch to our self-serve method of publishing via the .asf.yaml meta-file. We aim to turn off gitwcsub around July 1st.

1. 1. How to publish via .asf.yaml:
      Publishing via .asf.yaml is described at: https://s.apache.org/asfyamlpublishing
      You can also see an example .asf.yaml with publishing and staging profiles for our own infra web site at: https://github.com/apache/infrastructure-website/blob/asf-site/.asf.yaml

In short, one puts a file called .asf.yaml into the branch that needs to be published as the project's web site, with the following two-line content, in this case assuming the published branch is 'asf-site':

publish:
whoami: asf-site

It is important to note that the .asf.yaml file MUST be present at the root of the file system in the branch you wish to publish. The 'whoami' parameter acts as a guard, ensure that only the intended branch is used for publishing.

1. 1. Is my project affected by this?
      The quickest way to check if you need to switch to a .asf.yaml approach is to check out site source page at https://infra-reports.apache.org/site-source/ - if your site is listed in yellow, you will need to switch. This page will also tell you which branch you are currently publishing as your web site. This is (should be) the branch that you must add a .asf.yaml meta file to.

The web site source list updates every hour. If your project site appears in green, you are already using .asf.yaml for publishing and do not need to make any changes.

1. 1. What happens if we miss the deadline?
      If you miss the deadline, don't fret. Your site will of course still remain online as is, but new updates will not appear till you create/edit the .asf.yaml and set up publishing.

1. 1. Who do we contact if we have questions?
      Please contact us at users@infra.apache.org if you have any additional questions.