Update Plone 5 to 5.0.3

[svx]

Plone 5.0.3 is out

We need to do:

• update/add 5.0.3
• add docs about how to do that

[avoinea]

• Added 5.0.3 tag
• Updated 5.0 and 5 tags to point to the latest release

Alpine builds are crashing

[avoinea]

About documenting this:

Right now the release process is manual by adding/updating tags on Docker Hub within Build Settings section.

But, I think we should wait for this PR docker-library/official-images#1434 to be approved, and then update documentation.

[demarant]

@avoinea docker just replied to our PR on official image docker-library/official-images#1434 (comment)
we need to quickly reply when things are hot on that front ;)

plone does not eed zeo .. it is just for the clustering option we could reply...but we can give the zeo image as well. we already have a zeo image https://hub.docker.com/r/plone/zeoserver/

[avoinea]

Already released 5.0.3 sometime age. There is a different ticket for documentation