Fix support for string repo values

[eerohele]

Leiningen allows repo definitions to be either strings (e.g. "https://download.java.net/maven/2") or maps ({:url "https://download.java.net/maven/2"}). deps.edn only allows maps, so if project.clj has a string, we'll need to convert it into a map.

[borkdude]

Thanks. Do you need another release or can you use this via deps.edn?

[eerohele]

I can use it via deps.edn. Thanks!