Search whole repo for file

[kequach]

I noticed that repositories sometimes have a citation file that is not in the root folder. This leads to has_citation being false, which is incorrect. Searching for files should also include subfolders.
Tested with the following repository: https://github.com/amices/mice
Citation file location: https://github.com/amices/mice/blob/master/inst/CITATION

Screenshot of howfairis analysis: