ci: upload tagged AppVeyor installers as GitHub releases

ci: upload tagged AppVeyor installers as GitHub releases

Deploy Windows installers built by AppVeyor as releases on GitHub. This
process is triggered only when tags are uploaded to the repository.

Patch was created using this guide:
https://www.appveyor.com/docs/deployment/github/

- Generate a GitHub authentication token with public_repo scope:
  https://github.com/settings/tokens
- Login to AppVeyor and encrypt GitHub token: Account -> Encrypt YAML
  https://ci.appveyor.com/tools/encrypt
- Insert encrypted token in appveyor.yml on the secure: line under
  auth_token:

With APPVEYOR_REPO_TAG set to true only tags pushed to GitHub will have
Cygwin MSI installers uploaded as releases to GitHub.

Signed-off-by: Vincent Fu <vincent.fu@samsung.com>
Link: https://lore.kernel.org/r/20220808175133.37920-2-vincent.fu@samsung.com
[axboe: replace token with right one]
Signed-off-by: Jens Axboe <axboe@kernel.dk>