[darc/maestro++] Add `--regex` option to `darc get-repository-policies`

[mmitche]

@dougbu commented on Wed Jul 03 2019

darc get-repository-policies lacks options that could / should be copied over from darc get-subscriptions. The one I miss the most is --regex. --exact is also applicable but I've never needed that one.

For example, the following command displays information about policies in AspNetCore-Tooling as well as the hoped-for AspNetCore information

darc get-repository-policies --repo https://github.com/aspnet/AspNetCore --branch master