This PR adds the `nolink` dependency type to r- package dependencies.
This is needed due to the new dependency types in Spack. A couple of
packages were updated with new versions as well.
A while ago I was asked to convert packages to all lowercase. That was
done but some dependencies did not get converted in the specification.
This commit fixes that as well as a couple of urls that need to be made
explicit and a missing dependency on jdk.