Support for soft purging all

[StarWar]

The current method purge_all does a hard purge. I need a method to support soft purging as well.

    def purge_all
      fetcher.client.post("#{Service.get_path(id)}/purge_all")
    end

[Integralist]

Hi @StarWar thanks for opening this issue.

If you review the documentation for the purge_all API endpoint it states:

Purge-all requests cannot be done in soft mode and will always immediately invalidate all cached content associated with the service. To do a soft-purge-all, consider applying a constant surrogate key tag (e.g., "all") to all objects.

With that in mind, I'm going to close this issue but please do feel free to continue the conversation here if you have any further questions.

Thanks.