Repo owner detection breaks for repos containing . in their name

[benhiller]

I tried using spr with a repo, but git spr status failed with the error: unable to auto configure repository owner - must be set manually in .spr.yml.

I believe the issue is because the repo name contains ., and repoFormat only allows \w and -. This is sort of a similar issue to the one fixed in https://github.com/ejoffe/spr/pull/393/files.

Creating a repo on Github shows that it allows: "ASCII letters, digits, and the characters ., -, and _" in repo names. Would it be reasonable to modify the regex to match all of those? Maybe adding . would cause issues with matching the .git suffix though.