Repository links should go directly to READMEs, not to root of GitHub repository

[pmonks]

Typically when a visitor is looking at the project catalogue and wants to drill down for more information, it's the README file in the project's main repository that they're after.

Right now, however, the repository links on the project catalogue cards drop the visitor into the default GitHub homepage for the repository, which shows the source code for the project before the README, which often results in the README dropping below the fold. It would therefore be preferable if, instead of dropping the user to the default GitHub repository page, we dropped them directly onto the README.

For example, the plexus-interop repository link on the Plexus card would go to:

https://github.com/symphonyoss/plexus-interop/blob/master/README.md

instead of:

https://github.com/symphonyoss/plexus-interop

[pmonks]

(this feedback came from a community member)