Add Winget Releaser workflow

[sitiom]

This action automatically generates manifests for WinGet Community Repository (microsoft/winget-pkgs) and submits them.

Notion Enhanced is already in Winget, and this workflow will be used to update it.

Before merging this:

1. Add a classic PAT with public_repo scope as a repository secret named WINGET_TOKEN. You can go to this URL to create it: https://github.com/settings/tokens/new?scopes=public_repo

2. Fork https://github.com/microsoft/winget-pkgs under @notion-enhancer. The action will use that fork for making a branch and creating a PR with the upstream winget-pkgs repository on every release.
3. Use Pull to ensure the fork is constantly updated.

If you want to see an example of a PR created using this action, see microsoft/winget-pkgs/pulls (Pull request has been created with WinGet Releaser).