[Bug 42735] New: Add Debian testing WineHQ repository

https://bugs.winehq.org/show_bug.cgi?id=42735

Bug ID: 42735
           Summary: Add Debian testing WineHQ repository
           Product: Packaging
           Version: unspecified
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wine-packages
          Assignee: [e-mail]
          Reporter: [e-mail]
                CC: [e-mail], [e-mail]
      Distribution: ---

Currently, Wine HQ debian repo provides named repositories for: wheezy, jessie,
stretch, sid. See https://dl.winehq.org/wine-builds/debian/dists/

Please add one for "testing", so users of Debian testing wouldn't need to refer
to specific named releases.

Wine staging Debian repo used to do that, but now it's being deprecated.