build(versions): Cleanup unused buildout config

Chanced across this while updating the `Products.PluggableAuthService` version.  The
`./versions.cfg` file isn't referenced anywhere that I can see.  A `./versions.cfg` file
is a convention in the Plone world so it's misleading to have an unused one lying
around.  A developer might reasonable assume that a change in that file should take
effect.

Author: rpatterson

Makefile

@@ -26,7 +26,6 @@ update: ## Update Make and Buildout
 	wget -O requirements.txt https://raw.githubusercontent.com/kitconcept/buildout/5.2/requirements.txt
 	wget -O plone-5.2.x.cfg https://raw.githubusercontent.com/kitconcept/buildout/5.2/plone-5.2.x.cfg
 	wget -O ci.cfg https://raw.githubusercontent.com/kitconcept/buildout/5.2/ci.cfg
-	wget -O versions.cfg https://raw.githubusercontent.com/kitconcept/buildout/5.2/versions.cfg
 
 .installed.cfg: bin/buildout *.cfg
 	bin/buildout