Add pattern matching to input files

[m-roberts]

Closes #3

Update: this has been tested with a single .dsc file match. Basic testing of the concept suggests that this should scale properly.

[lpenz]

Thanks you for looking into this

I think you mentioned in issue #1 that we can't upload multiple packages.
Is this to avoid hard-coding the .dsc file name?

Also, shellcheck seems to have found a few issues.

[m-roberts]

Our main intention was to be able to upload a complete Debian package (including source) to PackageCloud with one action step.

You can see what we are doing here, which has a few commits addressing a couple of different things that we wanted.

[diff]

It's possible that some other changes were made to this other than what is presented in this PR - you may wish to simply review this yourself to see if you wish to use any of it - we are likely to continue to use our fork.

[lpenz]

Wow, you do have a lot of local changes.
Cool, I'll take a look into this part, let me know if you have other interesting things there.